I assume that when you say "using DOS" you mean that you have a FP DOS (some version) application which you sometimes use.
If that is true, remember that FP DOS does not really recognize Windows or use any of the Windows print drivers. Instead it merely outputs its print data to one of the hardware printer ports (LPTn or COMn). That is why Windows has to be configured to "capture" output attempts to the LPT (or COM) ports and re-direct them. Additionally, Window's ability to successfully accomplish this task could be rated at best as being on the "flaky" side.
Converting the DOS application to one of the FP Windows versions (FP 2.6 Windows or Visual) will enable the application to recognize and successfully utilize the Windows print drivers.
Good Luck,
jrbbldr
jrbbldr@yahoo.com