If the errors occured before going to 6.1 (which is when many issues like this made themselves known), then chances are it's something with your local setup that is going awry than something that the UBB is directly causing.

The file not founds within the logs are just that - clients requesting files that aren't there... <img src="https://www.ubbcentral.com/boards/images/graemlins/smile.gif" alt="" />

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Charles Capps
Programmer, Infopop Corporation
Please do not contact me privately for support - post on the board or open a support ticket instead!