Well guys...Ive been trying to find a solution for this thing quite few 
days but could not reach anything till now!

Im simply trying to implement a very small system (muliplierbsb--in 
attachmenet) to send and receive data through the microblaze to my 
core(Muliplier_VHDL.

I created a core(user_logic) in XPS with 3 slave registers. Inside this 
core I used a multiplier core(Muliplier_VHDL) which I designed.

My aim is to write to the slave registers from the microblaze and then 
read the values in the registers by Muliplier_VHDL core and the write 
back to a register to be able to read the value written to this register 
from the microblaze again.

After implementing this and trying to download the bit stream I had the 
following errors

ERROR:NgdBuild:455 - logical net 'clk_100_0000MHz' has multiple 
driver(s):
pin PAD on block lmb_bram/lmb_bram/clk_100_0000MHz with type PAD,
pin CLKOUT0 on block
clock_generator_0/clock_generator_0/Using_PLL0.PLL0_INST/PLL_INST/Using_ 
PLL_A
DV.PLL_ADV_inst with type PLL_ADV
ERROR:NgdBuild:924 - input pad net 'clk_100_0000MHz' is driving 
non-buffer
primitives:
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Byte_Enable_0 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Byte_Enable_1 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Byte_Enable_2 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Byte_Enable_3 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Write_Data_0 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Write_Data_1 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flo
w_I/Byte_Doublet_Handle_I/MEM_D
ataBus_Write_Data_2 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Write_Data_3 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Write_Data_4 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Write_Data_5 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Write_Data_6 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Write_Data_7 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Write_Data_8 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Write_Data_9 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Write_Data_10 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Write_Data_11 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Write_Data_12 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Write_Data_13 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Write_Data_14 with type FDRE,
pin C on block
microblaze_0/microblaze_0/Performance.Data_Flow_I/Byte_Doublet_Handle_I/ 
MEM_D
ataBus_Write_Data_15 with type FDRE
ERROR:NgdBuild:809 - output pad net
'muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/Out_1_s<0>' has an illegal 
load:
pin I4 on block 
muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/IP2Bus_Data<29>1
with type LUT6
ERROR:NgdBuild:809 - output pad net
'muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/Out_1_s<1>' has an illegal 
load:
pin I4 on block 
muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/IP2Bus_Data<30>1
with type LUT6
ERROR:NgdBuild:809 - output pad net
'muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/Out_1_s<2>' has an illegal 
load:
pin I4 on block 
muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/IP2Bus_Data<31>1
with type LUT6
ERROR:NgdBuild:455 - logical net
'muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_1_s<2>' has multiple
driver(s):
pin Q on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_1_s_2 with
type LD,
pin PAD on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_1_s<2> 
with
type PAD
ERROR:NgdBuild:924 - input pad net
'muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_1_s<2>' is driving 
non-buffer
primitives:
pin Q on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_1_s_2 with
type LD
ERROR:NgdBuild:455 - logical net
'muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_1_s<1>' has multiple
driver(s):
pin Q on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_1_s_1 with
type LD,
pin PAD on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_1_s<1> 
with
type PAD
ERROR:NgdBuild:924 - input pad net
'muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_1_s<1>' is driving 
non-buffer
primitives:
pin Q on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_1_s_1 with
type LD
ERROR:NgdBuild:455 - logical net
'muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_1_s<0>' has multiple
driver(s):
pin Q on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_1_s_0 with
type LD,
pin PAD on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_1_s<0> 
with
type PAD
ERROR:NgdBuild:924 - input pad net
'muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_1_s<0>' is driving 
non-buffer
primitives:
pin Q on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_1_s_0 with
type LD
ERROR:NgdBuild:455 - logical net
'muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_2_s<2>' has multiple
driver(s):
pin Q on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_2_s_2 with
type LD,
pin PAD on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_2_s<2> 
with
type PAD
ERROR:NgdBuild:924 - input pad net
'muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_2_s<2>' is driving 
non-buffer
primitives:
pin Q on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_2_s_2 with
type LD
ERROR:NgdBuild:455 - logical net
'muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_2_s<1>' has multiple
driver(s):
pin Q on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_2_s_1 with
type LD,
pin PAD on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_2_s<1> 
with
type PAD
ERROR:NgdBuild:924 - input pad net
'muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_2_s<1>' is driving 
non-buffer
primitives:
pin Q on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_2_s_1 with
type LD
ERROR:NgdBuild:455 - logical net
'muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_2_s<0>' has multiple
driver(s):
pin Q on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_2_s_0 with
type LD,
pin PAD on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_2_s<0> 
with
type PAD
ERROR:NgdBuild:924 - input pad net
'muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_2_s<0>' is driving 
non-buffer
primitives:
pin Q on block muliplierbsb_0/muliplierbsb_0/USER_LOGIC_I/In_2_s_0 with
type LD

------------------------------------------------------------------------ 
---

when I synthesize and implement the design in ISE it does not give any 
errors, errors only appear when trying to download the bitstream in XPS

I do Understand that there is something wrong with the clock and that it 
has multiple drivers, but how can I find this and how can I fix it. Is 
it something in the pin assignment?

Also concerning the other signals, I totally have no idea whats going 
wrong.

Its my first time to try to integrate a whole system together and 
communicate with the microblaze, any advice concerning this will be 
appreciated.

Thanks,

Eshbon