SAN disks appears empty

[Pedro_28]

I have upgrade the firmware in a SAN Switch 2/16-EL from v3.2.0 to v3.2.1b, do a reboot and everything seems fine. Triying to upgrade to v4 was impossible. Then I have detected a problem in two servers, because there are others functioning perfectly. That servers use Windows 2003. I see the disks belonging to the SAN but they are empty. From Replication Manager I see the Pools but the units are without letter and from Windows explorer I don't see the units. I don't have secure path, only one switch and one MSA1000. I have restarted the switch, enabled the configuration but nothing changes. Also I have restarted the servers and the same. From my point of view, Windows seems to have lost something in the disk configuration.
Any help will be appreciated.

Peter