Backup Exec 10.0 Slowdown

    I realise that there have been a few threads about this already, but they did not really help me out too much. We are running our backup on a Dell PowerEdge 2600 with Quantum DLT Tape drives, and using QUantum DLTape VS1 Tapes. For ther past month we have noticed that it is taking longer and longer to do a backup of our system. My manager has stated that it is hanging up on the exchange server. Our backup starts at 7p.m. every night, and sometimes is still not done by 4:30p.m. the following day. Any suggestions?