What kind of install are you using? I have not had any success using lilo with backtrack or any linux distro for that matter, was installed in the "live" format, with or without changes. I could very well be wrong, but I believe you have to use a full HD install for lilo to work properly. There's a great video tutorial by muts for that here:http://www.offensive-security.com/mo.../dualboot.html
It shouldn't be too difficult to adapt it for your needs.
Hope this helps.