Okay I used this tutorial on the "Generated an incorrect block. Waiting for the next one..." bug on NRS 0.5.11:

https://nextcoin.org/index.php/topic,1675.0.html

Downloaded the latest NXT-files and then it all updated. Working fine now.

But one question. My forged 200 NXT are gone? Didn't they make it into the blockchain?

Here a comparison of the working client and the corrupt:

http://i.imgur.com/XgFaDBr.png

Any ideas?

Greetings,

Silv0r