I have been using my backtrack version 5 on the Virtualbox for some time now but I had a resolution problem and after searching found out I better install VirtualGuest additions. However after installing it startx does not work anymore and gives me segmentation fault. as follows:Segmentation fault at address 0x7f7b26129800caught signal 11(segmentation fault). Server abortingPlease consult the http://wiki.x.org foundation supportPlease check the log file at var/log/Xorg.0.log for additional information.ddxSigGiveUp: closing log giving up. xinit: no such file or directory (errno 2). unable to connect to x server. xinit: no such process (errno 3). Server error. 
Startx Segmentation fault error after installing VirtualGuest Additions for Virtualbox
virtualbox;backtrack;x server;segmentation fault;startx