Yeah I have had that problem too. To add to what the others have said . . .
I have had some issues but all worked out in the end. This is the order of operations that worked for me most of the time.
1. Install newest Novell Client on PC.
2. Install Windows Messaging NTWMS.EXE.
3. Install GW client 5.5.4 or higher,
4. If anything goes wrong, and it has, I had to completely uninstall NTWMS & GW (sometimes even using the cleanup tool for GW), and then trying it all over again.
Hope some of this helps - much of it is a repeat of what others have said, but just letting you know that it can and should work. Keep trying and good luck.