Component One Licenses.licx throws an Exception

Component One Licenses.licx throws an Exception

Hy Guys,
After we decided to buy an C1 License for the Silverlight FlexGrid
Component we were wondering why the activation won't work.
The Dialog Shows up that the copy of C1.FlexGrid is activated, but however
after we published our Silverlight Addin we still get the Message that C1
is not activated.
After a long time of Research we found out that no licenses.licx file was
created.
So we created the file manually with the following entry:
C1.Silverlight.FlexGrid.C1FlexGrid, C1.Silverlight.FlexGrid.5
Afte Rebuilding the whole solution we get an Invalid-Cross threat Access
Exception right from the licenses.licx file.
Error 1 Exception occurred creating type
'C1.Silverlight.FlexGrid.C1FlexGrid, C1.Silverlight.FlexGrid.5,
Version=5.0.20131.311, Culture=neutral, PublicKeyToken=***************'
System.UnauthorizedAccessException: Invalid cross-thread access.
Any Suggestions?