I would like to obtain a copy of this program as well.
The fact that it's for exclusively for commercial UNIX workstations (AIX, Solaris, IRIX or HP-UX) won't be an issue at all. Given the age and system requirements, it is proving very hard to come by.
I am of the understanding that CATIA V4 release 2.5 is the last version of V4 (c. 2006)
If someone has a copy, please reply to this message here.