Eclipse won't start after installing plugin

[Lokikol]

I'm using Eclipse Luna (4.4.1).

I downloaded the .zip file, and extracted the .zip into the dropins folder.
Afterwards, eclipse won't start, until I delete the dropin.

I tried to put the .jar file directly into the dropins, I tried to put it into
dropins/plugins/file.jar and I tried the same with /plugins instead of dropins.

Everytime it's the same. Eclipse won't start until I delete the file again.

Thanks