[TYPO3] Corrupt Extension Manager

[Chris Bischoff]

It seems that I have a corrupt extension manager. I cannot load or unload
extensions with it. I have to manually add or remove the extension key to
the extList in the Install tool. This started to happen only recently when I
was trying to use the calendar (Extended Calendar) extension to replace the
tt_calendar one. Can anyone please suggest a fix? Thank you!

~Chris