Removing reference with PDF docs

I import a collection of PDFs from a folder, which lands in the ALL references library. For a certain set of PDF documents, I am not able to move them, delete them, or clear them. It seems to be a problem with the PDF documents because when I delete the PDF from the folder in myendonotelibrary.data folder, then I am able to move or delete the item directly in endnote. I can also delete the item in my library by deleting the PDF directly in endnote. Is this a common problem with PDF documents?

Using X5 on Windows 7.

Help please! Thank You!

Greetings,

I haven’t of this particular behavior, but I would like to get a copy of your problematic library to test on my workstation.  I will be creating a support case for troubleshooting purposes. 

Best Regards,
Jimmy M.
Customer Technical Support Representative Scientific
Thomson Reuters
Phone: +1 800 336 4474
ResearchSoft Product Support
thomsonreuters.com