ARM-USB-OCD with STR750 configuration

Has anyone used an Olimex ARM-USB-OCD with OpenOCD on an STR750 chip?  I
can program the flash but have no luck running gdb.  As soon as I try to
start or jump to an address gdb disconnects.  The flash is programmed
correctly because the program runs fine without debugging.

The problem occurs on both a Reva 2.10 board with STR750 daughter and a
custom STR750 board.  The config file is:

#daemon configuration
telnet_port 4444
gdb_port 3333

#interface
interface ft2232
ft2232_device_desc "Olimex OpenOCD JTAG A"
ft2232_layout "olimex-jtag"
ft2232_vid_pid 0x15BA 0x0003
jtag_speed 19

#use combined on interfaces or targets that can't set TRST/SRST
separately
reset_config trst_and_srst srst_pulls_trst
jtag_nsrst_delay 500
jtag_ntrst_delay 500

#jtag scan chain
#format L IRC IRCM IDCODE (Length, IR Capture, IR Capture Mask, IDCODE)
jtag_device 4 0x01 0x0f 0x0e

#target configuration
daemon_startup reset

#target <type> <startup mode>
#target arm7tdmi <reset mode> <chainpos> <endianness> <variant>
target arm7tdmi little run_and_halt 0 arm7tdmi
run_and_halt_time 0 30

working_area 0 0x40000000 0x4000 nobackup

#flash bank <driver> <base> <size> <chip_width> <bus_width>
flash bank str7x 0x20000000 0x00040000 0 0 0 STR75x

#allow gdb to query memory map
gdb_memory_map enable

I tried with OpenOCD r141 and OpenOcd r247, gdb 6.5 inside Eclipse 3.2
and 3.3, same problem in all combinations.  gdb startup is:

target remote localhost:3333
monitor reset
monitor sleep 500
monitor poll
monitor soft_reset_halt
monitor arm7_9 force_hw_bkpts enable
symbol-file c:/gccfd/projects/rack750/Rack750.elf
info mem
thbreak main
jump _start

gdb hangs on the jump until I kill the OCD task with r141.  Using r247 I
get a message that the OpenOCD server dropped the gdb connection.