I believe an 'eggdrop' is a script which runs in the backqround and used to keep news servers running. It is definitely not part of CalendarScript but a flaw in earlier versions could allow malicious files to be uploaded and executed on your server.
You should upgrade to a current version of CalendarScript to help prevent such files from being uploaded. The offending files should be able to be disabled or deleted without negative effect to the calendar program.
Dan O.
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