delete key funny character

[firecrow silvernight <fire%firecrow.com@localhost>]

Hi,
im having an isaue in xterm where the delete key shows ^? instead of normal 
behavior.

it doesnt happen all the time, when it starts it stays.

happens in xterm and tmux and nvi and vim, but not always at the same time, 
an xterm bash shell may be ok, but the vim session spawn from it may be broken.

any thoughts on how to configure this, or more helpful information i should 
dig for, welcome.

~fire