Source:  GroupWise Exchange Gateway.

Explanation:  If you are installing a new version of the gateway while an older version of the gateway exists on the server, the Installation program tries to replace the gwproxy.dll, but the process cannot be completed because the existing version of gwproxy.dll is loaded into memory.

Action:  Remove gwproxy.dll from memory. You can do this by stopping the System Attendant service and restarting it immediately. You can then click Retry. Do not click Retry before the services and their dependencies have started.