Windows Groups and Write location is protected

Hi,

I'm working on a project that uses Windows Groups in the Plant Scada Security Roles. Each group has its own privileges set to restrict user access.

I am encountering a problem that returns the Generic Error, 9 Write location is protected. The user in the Windows Group has the correct privilege however when they carry out a write operation, the initial operation works fine but when they attempt to do another operation it fails with the Generic Error 9.

Has anyone else observed this behaviour when implementing Windows Groups?

Any advice would be greatly appreciated.

Thanks,

Gavin