I can't "next" or "step" in insight!

Hi support,

I can't do "next" or "step" in insight.
When I press the button, the
green highlighted line stays where it was. So I opened a gdb
console
in insight and type "n", this time it showed:

(gdb) n
Error: Warning:
Cannot insert breakpoint -11.
Error accessing memory address 0x29be0: Input/output error.

I reinstalled insight and gdb, and the problem remained.

I'm using Ubuntu 7.04, GNU gdb 6.6-debian, but "insight
--version"
shows "GNU gdb 6.5".

Thanks a lot!