Unknown error 22 is a windows error message - this error indicates there has been an network interruption.
There are two main variants of this issue with different solutions.
Error 22 occurs periodically and after restarting ConQuest does not occur again immediately
This is usually a connectivity issue. Especially if you are accessing ConQuest across a VPN or you are using a wireless network within the office, ConQuest may be losing contact with the file share.
If it tends to happen mostly after ConQuest has been idle for some time, then it could be related to network card driver power-saving settings.
However the Group policy running in the background is the biggest cause of this issue, due to a setting with the Group Policy drive mappings which causes it to delete and re-add the mapped drives. This is not an issue if this policy is applied only at startup, but many companies have their Group Policy set to run at scheduled intervals throughout the day.
Error 22 occurs consistently
This is most often a permissions issue. The log file and error message will usually indicate what, exactly, ConQuest is having trouble accessing. Your IT's assistance will likely be required to repair the permissions on the resource in question.
This can also be due to corruption in the project, so if you have issues only on a specific project, first try a Check Job from the tools menu, and if that doesn't help raise a call as detailed below.
The ConQuest log file and Windows Event Viewer should assist your IT in resolving this issue for you.