I figured it out- xev said backspace was 0xffff (Delete). So I did a
xmodmap -pk | grep ffff, and found out my backspace key (188) was bound to
it. so a simple xmodmap -e 'keycode 188 = BackSpace' took care of that.

thanks

> >I'd especially like to fix the rxvt problem, since
> >I prefer rxvt to xterm, and the backspace doesn't work in any other app
> >other than xterm and a few athena-based apps.
> 
> I normally use rxvt running on pmax and displaying on an X terminal, and
> I have no problems. Backpace sends ^H and arrows send ^[[A through ^[[D
> as they should.
> 
> Some questions that may help isolate your problem:
> - Do you mean rxvt running on the pmax and displaying on another display,
>   or running on another machine and displaying on the pmax display?
> - Are you using the rxvt package or one you built yourself? If you build your
>   own, try setting FORCE_BACKSPACE in feature.h. If you use the package one,
>   check that your stty erase key is ^H.
> - Does the X server send the right event when you press the backspace key?
>   (If you run xev and press backspace, do you get 'keysym 0xff08, BackSpace',
>   or something else?)
> -- 
> Kevin Schoedel
> schoedel@kw.igs.net
>