In case the CUSTOMTOOLS is being used to fill up the document Properties, the Check In operation to the SOLIDWORKS PDM fails and the user gets an error message telling that the user does not have proper user rights to check in files to the SOLIDWORKS PDM Vault.
This problem could occur because of the May see files before check in (Private state) option in the SOLIDWORKS PDM. Clear selection of the SOLIDWORKS PDM option above to make the user allowed to check in the documents again.