By default, PaperCut will monitor all printers on the system/server. Deleting the printer via the web interface will not stop monitoring - the printer will just reappear next time a job arrives.
To completely ignore a printer, the Print Provider component needs to be instructed not to track activity. This procedure is explained in the user manual section Adding and Removing/Deleting/Ignoring Printers, available online here:
This release contains an updated Java version which no longer supports 32-bit workstations. If you have any 32-bit users launching the User Client or Release Station from a network share, see this Knowledge Base article for more information.