With such a helpful description, one answer is as valid as another.
There should be log files for you to sift for clues. Most likely it
is hanging up trying to find some nonexistent or misplaced
feature, or license service. This is all administrator stuff, but
also there are dependencies on certain user dotfiles. Start
by looking at someone's setup who has it working.
at what point does it hang?
never see the splash screen? probably wrong color depth or wrong X display settings
after seeing the CIW window? in that case read/post the error message in $HOME/CDS.log