If you want to print from a DOS program to a network printer, you have to bind the printer port used by the particular DOS program to the network printer path.
For example, let's say your DOS program prints to LPT1 (most DOS programs do) and your printer is on the network at the following network path:
\\MY_SERVER\PRINTER
Go to the "DOS/Command Prompt"
Type the following command:
NET USE LPT1: \\MY_SERVER\PRINTER
and press ENTER.