BigEdNY is probably right. The Windows 95/98/98se/Me family have "real" DOS windows and native support for LPT1, LPT2, etc. Windows NT, 2000, XP, 2003 all work on different principles. I see that your posts on June 6 and 7 confirm that going to the different Windows family is the basic issue. Now it's time for workarounds, but it's no fun.
On Windows NT, 2000, XP, 2003, the DOS window (now renamed Command Prompt) is "emulated", for lack of a better word, and so are LPT and COM ports. Most DOS prorams will work "as advertised" if you adjust them for the DOS-related issues, you know, reminds me of pounding a round peg into a square hole. With some issues, using a DOS window via the older but limited Command.com works better than Cmd.exe. Sorry, FoxPro for Windows was a hybrid, a limited Windows look and feel, but underneath it too was a DOS program.
Perhaps it is time to upgrade to newer Visual FoxPro with all its improvements, but of course the program will need some rewriting. Other posts here have talked about the DOS issues on the newer computers, but printing is the most common surprise. Also other posts on how to run program converters to get VFP to work on older code, perhaps not pretty, but working.
dbMark