And the rename operation was done using PDF Explorer own tools?
When using own tools this is not supposed to happen because database information is not changed when file renamed.
The metadata edition was done using what tool? InfoEdit, Import, EditInfoFileds Batch tool?
In some systems the InfoEdit tool, when using the QuickInfoEdit mode, fail to update the metadata in the PDF file itself, and only update the database, because the file opened in the InternalReader is locked by the reader external plugin and is not unlocked, at time, when PDF Explorer try to edit the file. This only occurs in some system, and I do not know why. Next version includes a check routine to present to the user a cancel/retry dialog when this happens.
So checks if when you edit the metadata the metadata is edited in the PDF itself (just open the file in Acrobat and check it). Sometimes changing the InternalReader settings (Edit>Preferences-InternalReader) from InternetExplorerDefault to AdobeAcrobat, or using the free Foxit Reader,
www.foxitsoftware.com/pdf/rd_intro.php, can fix these file lock problems.