You must not send a Maple worksheet file (name ending with .ms) to the printer! Instead, select the Print command from the File menu. This will pop up a Page Setup Dialog. Just as for a plot, you can save your worksheet to a PostScript file for later printing, but it is probably more convenient to send it directly to the printer. To do so, click on the button to the left of the text Printer Command: and then type lpr -Pmath or lpr -Pmath3 in the window to the right of this same text. Then click the OK button and your worksheet will be sent to the printer you selected.