will these errors over time cripple the .MDB file?
No, if they happen it will prevent an update rather than causing corruption. There is also a remote possibility that two players could lock each other out of the same record and both have to Ctrl-Alt-Delete but even then, no update would take place. The best idea is to try it as I am going on theory here rather than practical experience.
Steve
It is possible, but as Steve points out, at some point, a lockout will occur. Two players hopping into the same system?
One possible way around this, if Steve wants to do such work, would be to move from Access to the SQL Server desktop engine. It would require rewriting all of his database access code, and porbably a bit more. So I sort of doubt that it'd happen