I can't really say much more about our issue.
We had Fling configured to upload files every 30 minutes on one folder tree that contains log files written to very often, and confiured to upload automatically on any file change another folder tree that contains exes and config files etc that hardly ever change.
We have this exact same setup on several other computers without any issues, but on this particular computer I saw in task manager that the number of handles in use by Fling was continually growing.
Without being able to reproduce this problem I doubt you'll ever be able to fix it, the