I have a customer with a BM 3.7 to BM 3.7 VPN, using citrix at the HQ

(Master) to deliver apps to the remote (Slave) site.
Master is BM3.7 SP1, NW6 SP2
Slave is BM3.7 NW5.1 SP4

Users complain of the VPN dropping/disconnecting intermitantly
no work is lost)

I can only find 2 errors in the Activity logs for the master server
on slave server);
"An error occured while reading file SYS:_Netware\VPN|VPNMDB.DAT" -
i think is a hard disk error- a RAID 5 drive failed recently and was replaced.

"VPN Site-to-site licence is not available" when checked, both servers

display valid licenses, however TID 2950106 indicates that a site to
licence may be corrupt

has anyone else had experience of this or a similar problem?

thanks i advance