I've moved your question to the PADS Layout and Router community/ You should get a quick response here.
Something like that is very hard to debug with in this forum. Please contact our CSD (Customer Support Department) and possibly send the design. They will help you much more efficiently then in Communities.
Have you tried going around the board and selecting and/or trying to move parts (either one at a time or in small groups) to see if that causes a crash? That would/could identify a problem with a part or parts.
You could try something as simple as turning on the pin numbers (and maybe the signal names), turning off all but the Top layer, and scanning around to see if you see something. The repeat for the Bottom.
You could try exporting a net list, then importing it into a clean database to see if the problem reoccurs.
You could also try doing a compare of the exported net list to the board it came from, just to see if anything pops up.
Or you could try an ASCII-out/-in using one selection (some settings do require you to have multiple selections) at a time to narrow where the error is ocurring.
You can then zero in on what is causing the error.
I'd be willing to look at the board if you wouldn't get in trouble sharing it.
One other thing you could do is try loading the board into Router, then saving out as a PCB file. This will often fix problems.