It seems like an issue (related to long file/path name) that was addressed in a service pack. Download the latest service pack for 2013 (6.10) and try it again. The service packs are available on the support portal. Do you have access to it?

If it is still an issue then, file a support request.
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Best Regards,
Mandeep Singh
CADWorx & Analysis Solutions
Hexagon PPM