You might have a object on your layout that is corrupt. Try go to another layout that is totally empty that have the same Table occurrence just before you go into Find mode and then after you have searched, go back to your layout.
I would also set a extra If before you go to Order_List layout.
If ( Get(FoundCount) = 1 )
Go to Layout Order_Card
Else if( Get(FoundCount) > 1 )
Go to Layout Order_list
Go to Layout Order_Search/Card
Can you try first finding on the stored field, then constraining the found set by the unstorred calcs.
Give that a try.
You may have a damaged file or a screwed up index.
Nearly every time we have a new version of FMP released, I see at least one post where:
"It worked fine on the older version but now it crashes" or some such.
My hypothesis when I read that is that there may be an issue with the file that did not cause a crash with the older version, but does with the new. I have also observed problem files (it was a layout with a corrupted graphic and many versions ago) where it crashed in windows and not in Mac...
So you might recover the file and see what is reported by the recover process. You might also use advanced recover options and just rebuild all indexes. Then test the recovered or reindexed copy to see if the same script causes a crash.
Since this is probably a "live" hosted file in constant use, I'd do this test on a back up copy and see what results I get.
Notes about recover:
1) Recover doesn't catch all potential problems with a file
2) Recover can't repair every possible form of damage
3) Recover's repair of a file may not fully correct a problem
So if a file is found to be damaged, best practice, if possible, is to replace it with an undamaged back up copy. This may require saving a clone of the back up copy and importing all data from a recovered copy of your most recent copy of the file in order to produce an undamaged copy with up to date data.
4) But if you use advanced recover to only re-index the file (copy file blocks as Is), then this file should be identical to the original except for the new indexes and thus can be safe to use assuming that a messed up index was the only problem.