Please help.

After installed NW 6.0 SP5 on top of NW 6 SP2, tape backup can not operate
with Veritas BackupExec 9.1 The tape backup sometimes can backedup 200MB
data as well verified as normal complete, sometimes hung after backuped up
200MB data that tape drive did not response at all and hung the server as
well. The error message from BackupExec is "SCSI bus timeout". The server
backup was fine before applied SP5.

Here is the file of "startup.ncf"
load MPS14.psm
load SCSIHD.cdm
load nwaspi.cdm
load IDEATA.HAM port=1F0 int=E
load IDEATA.HAM port=170 int=F
load LSI_U3NW.ham slot=10008
load LSI_U3NW.HAM slot=10009

I have tried reinstall Backupexec 9.1 build 1158 but did not work.
Should replace the SCSI driver with old one which was working(came with
SP2) before applied SP5?

Please advice me how to fix it.

Thank you.