Startx Segmentation fault error after installing VirtualGuest Additions for Virtualbox

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 0x7f7b26129800 caught signal 11(segmentation fault). Server aborting Please consult the http://wiki.x.org foundation support Please 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.