How are you doing the printing?  If your PC is using terminal emulation to
connect to a UNIX server running the Pro-IV application and are using the
Pro-IV 'pass thru' printer, then the characters are probably getting munged
in the terminal emulation program.  Check the character set it is configured
for, and make sure that bits aren't getting stripped.  How you do this
depends on the emulation software you are running on the PC.

If the printer is connected directly to the system the problem is with the
printer definition tables maintained within Pro-IV.  You will need the
system reference manual to find out where the tables are and how to use
them.

If the application is running on the PC then you need to redefine the
printer type to match the installed printer or, more likely, to match the
custom printer driver that has been installed to enable Pro-IV to talk to a
Windows printer.  You can either select the correct printer type or define a
new one.   Again, you will need the system reference manual to find out how
to do this.

Be careful about casting aspersions simply because its old. Pro-IV is an
excellent example of an 'event driven' database programming environment - a
very powerful concept that more modern databases still haven't completely
caught up with.