This message means that the file Q++Server.EXE on the server needs to be updated. To do this:
1.Close Q++ on all workstations.
2.Sit in front of the SERVER computer.
3.Go to the folder C:\Q++ServerXE2\Updates\ and double-click on suqs.exe.
You will then get 2 messages, each informing you of the success or not of updating the Q++Server.exe and the nxServer.exe database engine.
Note that if you are running the ANSI version of Q++Studio, then you should follow the instructions here.