Hello Jim Clay,
as Rich Malloy indicates, when you use the VFYMOVBRM command, you haven't use the ADDTAPCTG after that.
Since you have insert previously the tape in a I/O slot, the command VFYMOVBRM execute automatically the insert process (in the category associated with the media class), places the tape in a empty slot and change the location in the BRMS inventory (you can view it with WRKMEDBRM).
Hope some of this helps.