I think there are several bugs here:

- The caster might not be a user, so this call can fail.
- After you delete an object, you need to immediately return so as to avoid running code on a deleted object.
- Since this check is on a timer, the caster could still have been logged out during the 1.5 second timer duration.  How much do we care about this?  It would be possible to set up a registration mechanism to delete these guys right away when the player logs off if necessary.

With these bugs it seems unlikely that the code was tested enough (or at all?).  Always check the server error windows to see if there are problems after making a code change.