Can't access dashboard anymore - 500 (Internal Server Error)

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Hey Guys,

i recently started building a concrete5 site and now ran into an error and i must say i'm stuck...

So:
I was working on the frontend, installed a custom block recently and everything was going fine, after a while i wanted to access the dashboard and saw that nothing was loading, the bar slides open but nothing gets loaded.

Console says this:
http://mywebsite.com/index.php/ccm/system/panels/dashboard?cID=195... 500 (Internal Server Error)
And in the response header:
{"error":{"message":"Call to undefined method stdClass::set()"},"errors":["Call to undefined method stdClass::set()"]}

I first thought that maybe my custom blocks screwed something up, so i deleted them via ftp but the error still persists (had no errors when installing the blocks).

So Frontend works flawlessly (editing, adding blocks etc), but accessing the dashboard is not possible anymore. I hope it was my mistake, otherwise just became scared of concrete5.

So anyone knows whats up? I would very appreciate it! Thank you in advance!