[thanks Alf, that thing blew out Chrome]

Bangobeat, could you place a sample file? Sounds like there is a constraint somewhere bugging you...

Sure i can, But dont facepalm when u see other 5 kg of mistakes. I would be very thankful if u provide me with Tips, at least basic ones!
http://www.speedyshare.com/files/281..._Recovery_.rvt
password ( if necessary) : fikekutevave

Well, I don't know what exactly went wrong, but here's how to fix it:

First, check out the attachment. This is the printout of the error message. Scroll all the way down to the last error: this is where you're getting into serious problems.
In the report you'll notice that all elements have an ID-number. Use this ID-number to identify the walls in question. To do this, go to the Manage Tab and choose Select by ID. Copy/Paste the ID-number into the field and press show. This will show you the walls accountable for the problems.
Now you can delete them right there, but it's also nice to know that you can do this in the error dialogue too. So try to change the wall thickness, and click through all warnings until you come to the part where you can't go any further. Select Expand, scroll down and expand the parts about the vertical layers. Check the walls, and select "Delete Checked Items".
Note: this isn't always possible, but it is possible to export the error report and delete the elements manually by ID.

Good luck!