Network Interruptions

We have implemented Window2000 Server (Domain Controller) with Win2k professional as clients running on DHCP. We have a win2k file Server in which Folders are Mapped as different drives to all in the networks. We also have WinNT 4.0 in which SQL 7.0is running. We have a unique problem in the Network. When I observe the Windows Explorer (after some time) there will a Disconnected Symbol like ‘X’ in all the Network Drives. But when I click on the Drives I will be able to access all my folders. This has created problem, where all Offline folder is created since it suddenly start Syncronizing and where all Sql client are running, they get sql error.

Can any one tell me why this disconnection of network drive is happening?

Diwakar