Filemaker scripted printing and otherwise from the windows world is tough. Here are some rules I follow with fmp 9 in order to usually have good printing results.
1. Make sure you have a postscript print driver installed for the printer, not PCL6 drivers.
2. Make sure that in the printer folder that you set your printer settings - Advanced tab - Graphic - TrueTypeFont - (select) Download as Soft Font
3. Set the printer as the default printer before entering filemaker pro. Do not switch printers during the printing cycle.
4. Always use the fixed page margins in the Layout Setup - Printing - Use Fixed Page Pargins. (especially if you intend to make a % reduction.)
If these all fail I save as .pdf and print it from adobe acrobat.
At least with fmp 9.0v3 the scripted printing usually works.
If we had a mac we would not have these problems.