Dynamic 4GL: Incorrect "User Limit Exceeded" error

When I try to run a Dynamic 4GL program, as soon as it attempts to open a window I get the error: Error(6017): User limit exceeded. Cannot run this program. This is nonsense, as no other d4gl processes are running. Before this, I had spurious -571 errors ('user not known on remote machine' or some such - which is also nonsense as I'm running the whole thing as Administrator on a stand-alone box). Then I changed the machine name (because it was in the wrong case) and userid (from informix/ Password to Administrator/ No Password) in setnet32. The whole thing has worked perfectly before. The only thing that's happened since then is that I've changed my modem and had to uninstall/ reinstall RAS. Can someone please help me recover from this little lot? -Andy Kent- Bristol, England.