It seems like your startx script is using korn shell or bash shell to export variables \(like "export VAR=value"\). Since Solaris uses bourne shell as default, you can try using korn shell before starting the startx script. You can also include \#!/bin/ksh or \#!/bin/bash in the first line of the startx script. That may solve your problem. Any problems, let me know.
About the new errors you got, you can search for xinit script in your system \(I�m not sure but it may be in /usr/X11R6/bin or something like that\). If you find it, you can do two things: you can put the full path in startx script \(line 81, as ksh tells\) or you can set-up your PATH environmental variable to include xinit�s path. If you set-up PATH variable you do not have ro change your startx script. Any problems let me know.