Welcome to the NetApp community. We'll all try to guide you !
Can you see an ISCSI sesion login sesion message in your syslog file on the filer ?
( /etc/messages )
Did you run through the ISCSI initiator setup on the Windows server ?
Did you add credentials for the filer in Snapdrive ?
It's usualy best practice to try creating the LUN through SnapDrive...
Wish you were in class here in Atlanta with us to help you through this problem.
I hope this response has been helpful to you.
At your service,
Eugene E. Kashpureff
Fastlane NetApp Instructor and Independent Consultant
(P.S. I appreciate points for helpful or correct answers.)