Data Protector Express not pulling new tape

[BVMike]

We recently took over IT support for a city that used DP Express 4.00-sp1. The full backup job runs until the end of tape. DP does not pull the next tape in the media set.

Four tapes are setup as part of a rotation and show up under home-Admin-Backup All-Weekly Rotation-weekly Set 1. They are all labeled as weekly set 1:1, 1:2 ..etc.

I'm lost at what to check next. I tried to create a backup set with another group of tapes with the same result.

Any suggestions on what to try?
The tape unit is a HP MSL G3 series library.