DataPro with Netware

I am running Netware 4.2 with DataPro Accounting Software for DOS. 2 of 3 users kept getting knocked out. Sometimes they would get a out of windows disk space, DataPro said it was a network error. I changed them to the Windows version of DataPro and now I get a run-time errors, DataPro says it is a windows error. Any suggestions on what to check where. I am a beginner manager of Novell Netware.