Unable to set an IO redirection terminal

[Nathan BIAGINI]

Hi,

i m a new user of gdb. I work on the last release of Debian Lenny and i ve installed last stable release of gdb to debug my C apps. 
I want to set the IO redirection terminal (cause my program need an input an output management). But, in the specified terminal (tty command of gdb), i get that : warning: GDB: Failed to set controlling terminal        :       Operation not permitted

I tried to use xterm but i get the same.

Regards.