hi,
the major difference between std edition and enterprise edition is support for more memory and MSCS clustering feature being enabled in enterprise edition. If windows detects the tape drives connected through the hba, netbackup should not complain.
Also, in the HCL, it says
9. Where support is shown for "Windows Server 2003 Enterprise Edition" and "Windows 2000 Server Standard", it is implied that the other versions of Windows Server
2003 and Windows 2000 Server are supported.
Check page 116
-Rajeev