if you still can't run FSB under VirtualBox, maybe I could help you...I am running VirtualBox for two years now. For me FSB is working fine (except some problems with importing tickdata or if I give FSB a lot of data to calculate I get sometimes an "out of memory" error).
VirtualBox 3.1.8 r61349
I have not used the deb package of VirtualBox, simply go the hard way and try compiling with "make", install VirtualBox tools and adjust the settings for RAM and VGA. Try also in fullscreen and window mode.
Tell if you could solve the problem
on VirtualBox I am running WinXP Pro gaming edition SP2 (I have experienced some problems with SP3)