op lock is short for 'opportunistic locking'. This is an issue relating to how windows deals with files on a server. . Best to just turn off oplocks/file caching and call it a day as Marvin suggested.
here is an explanation we have in our network docs here (from a veritest report comparing Netware 6 to Win2k)
"Opportunistic locking is an option, available in both NetWare 6.0 and Windows 2000 Advanced Server, that grants clients exclusive access permissions to files available on the shared server volumes. When opportunistic locking is enabled, the client is allowed to maintain locks on the files it accesses, and subsequent read and write requests relating to the locked files can be satisfied from a local cache. By allowing the read and write activity associated with a specific file to be cached locally on the clients,
opportunistic locking can greatly enhance overall file serving performance by significantly reducing the number of read and write requests that require physical access to the server disk resources.
Opportunistic Locking is a setting that is commonly used in the real world for performance enhancement; it is not a “benchmark special” setting. It is enabled by default on Microsoft servers. Opportunistic Locking is on by default for NetWare servers and Novell Windows 2000/NT Clients. NetWare’s Windows 9x clients default to
the Opportunistic Locking setting as off.
The function improves performance overall, but can be disabled if necessary when it may cause data corruption or have other adverse affects on application performance. Situations where a customer may wish to disable the function include the use of applications where a database is shared to multiple users, such as Microsoft Access, or ACT! from Interact Commerce Corp. for example.
To disable opportunistic locking in Windows 2000 Server requires a registry edit as outlined in Microsoft’s Knowledge Base article Q296264, Configuring Opportunistic Locking in Windows 2000
), which will disable Opportunistic Locking for all clients connected to that server. NetWare clients have an Advanced client property setting that controls the Opportunistic Locking ability of the client, and can be selectively enabled and disabled on a client by client basis. Opportunistic Locking can also be disabled on the NetWare server if desired, at the Client File Caching Enabled prompt in the NCP Parameters section when using the Monitor function, eliminating the function for all clients on that server."