There are two possibilites that I can thinbk of.
1. PRTDSKINF runs off a database that is built with the RTVDSKINF command. At the time the RTVDSKINF command was run, the library did exist. Since then it has been deleted. It will still show up on PRTDSKINF until the database is refreshed with another RTVDISKINF command.
2. The RTVDSKINF command is run with *SECADM authority. This will allow for gathering all the data on the system. Then the PRTDSKINF command just prints wahtever information that was put in the database. There is not authority checking for individual object. Your USRPRF is not authorized to library PVB062409B, so it looks to you like it does not exist.
So, first signon with QSECOFR authority and see if you can find the library. If not submit the RTVDSKINF command and view a new report when the build has completed.