This isn’t a common error, at least not in recent memory. In the past, you may have seen this if you tried to open a scene that wasn’t in a valid project, but Softimage no longer has a problem with that. To reproduce this error, I had to delete the system folder while I had a scene open.
crap error message. It says ‘segment’ because that’s was the equivalent of scenes was called in Sofftimage|DS (Segment, later renamed to Sequence) Never updated since 1997!