Are you using Removable Storage on the Windows2000 server attached to the SAN 
connected tape unit?, or are you using the drivers supplied by Tivoli (device 
drivers)?.

My server is NT based (not sure about the AIX based) and I am using the Tivoli 
drivers to connect to my tape storage. I noticed since I needed to disable the 
Removable Storage service on my Windows 2000 server attached to the SAN to get 
this to work correctly. Some how the 2 drivers were fighting for control, by 
disabling this service Tivoli's device drivers had no problem.

Joe