[TYPO3-dev] Can't create scheduler task - empty grey screen

[Sascha Orf]

Hello everybody,

I'm quite new to this so I hope I chose the right place to come up with my problem. I have searched for this issue yet and I found some bugs desrcibing this behavior but a solution was not among them.

Like the headline says, I'm trying to set up a scheduler task (I haven't set up any tasks yet).
When I click on "add task", the screen turns grey and that's it (the menu table on the left is still there).

Chrome gives me this message: "GET http://[myURL]/typo3/mod.php?M=system_txschedulerM1&moduleToken=c81da9265f4163bb02e79aea56474b3aa0fb6587&CMD=add 500 (Internal Server Error)"

I would be glad if someone could help with this issue. Thanks in advance!