Perform 'SHow LIBRary' to see what TSM thinks the situation is. I would start at the OS level, using tapeutil's facilities to check out accessibility and elements inventory of the library, to assure that it can all be used at that level. Whereas you apparently moved to a new platform, whatever that is, verify that the device driver through which you access the library and drives is modern and functional. Beyond that you may need to start over redefining library, paths, and drives, depending upon what you find. Look for OS logging of any errors which may point out problems.
Richard Sims