How are you "remotely accessing" this "shared data file"?
If this is a FileMaker file in a shared directory and the users are opening the file directly, then this is something the FileMaker Inc. strongly recommends you not do. This set up an easily result in your file becoming corrupted when two different users attempt to open the file at the same time. This corruption then, could explain why you are expreiencing frequent, random crashes.
Such shared files should be opened first with one copy of FileMaker--preferrably a copy installed on the same machine as where you put the file. Other users should then use Open Remote to find and access this database.
Regardless of whether or not you have shared the file in this manner, check it for possible file corruption. Open FileMaker without opening this file and choose Recover from the FileMenu, then select this file to recover it. If it turns out that your file is damaged, best practice is to not use the recovered file, but to replace it with an undamaged back up copy if at all possible.