Hi andras,

I think there are several issues here, I've untrimmed your surfaces and found there were duplicate surfaces, one on top of each other.
Once deleting them I still had problems trimming, then I found that your model was about 40978 units long and 1862296 units away from the origin which are quite huge numbers, so I believe it would be a fitting tolerance problem where Moi is having a hard time getting the accuracies of 0.001 for such large numbers, Michael explains this in several posts with some guidelines:

http://moi3d.com/forum/index.php?webtag=MOI&msg=2445.35
http://moi3d.com/forum/index.php?webtag=MOI&msg=2418.4

The next step was to scale the model way down to a scale factor of 0.01 and bring the model closer to the origin and this seemed to fix the problem, then I re scaled back to your original size.
I would recommend to finish everything at a smaller scale then final scale to the size you want as the very last operation if you need these dimensions at final output.


Cheers
~Danny~