(Booted to Port folder.)
Yep, we've had a few people with the German version of the game experience this recently.  
Here's the longest thread on the issue.  There was never a definitive solution provided, though you should be able to click Cancel through the error message and keep playing.  Let me poke around the Wiki and see if I can come up with a better solution. 

Edit: Okay...let's see if this fixes things.  Download the attached table file, and plop it in the folder FreeSpace2/fsport/data/tables.  You'll probably have to create those two folders yourself.
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