It probably means that the path of a file (which inlcudes the folders and the file name and its extension) is longer than the 256 character limit supported by Microsoft Windows.
If there are many levels of subfolders or very long file names etc, this will cause a long file path and possibly exceed the Windows limit.
It's just like Prasad said, the file name with extension plus the entire path is over 256 characters. I get some people that are verbose in their descriptions and then bury them deep inside a folder structure.
Look at the folders and the file names and see if all of the words are needed or if some can be abbreviated. Sometimes the depth of the folder structure is not needed and can be reduced.
Same situation was for me before but when i installed long path tool, my computer was free from any path long errors and it will help you also in this situation
How do I install duplicate files deleter? I need to organize my computer.
I have worked with PDM Works Enterprise, Enterprise PDM, & PDM Pro for the last ten years and this error comes up from time to time.
I have found this happens when the following equation equals more than 256 characters:
Complete folder path length (minus drive letter) + file name length (with extension) + version count = 256+
"\EPDM\Projecte Confectii Metalice\Fincantieri Cruise 6226 Silversea - VARD ELECTRO\filename 123.sldprt" = 102 characters
If a file in this folder has 154 versions, which is common, that equation seems to trigger PDM slowing down, behaving erratically, email notifications stopping, etc. and you will begin seeing this error without explanation and won't be able to check in files in those folders. If I remember correctly, I also don't think this error appears in the log.
Try this - rename those folders you have selected to a very short name and try the operation again and let us know if it helped.