Welcome to the forums.  And Mac, too. 

I am not 100% sure if this will help.  Try printing and choosing save as pdf at the bottom left corner of the dialogue.  Also, try export.  To get consitency and easily go through the trial and error process use the Page Setup Manager.......

I think you will need to add a printer.  In Mac system preferences /Printer dialogue click the "+" add printer button.  Choose the "IP" option. In the "address" field type "1" wait for the "add" button to become active.  YOu can use a generic postscript printer. Or you can select to use "selected Printer Software"  Choose the wide format printer of your liking.  I use HP t2300 PLC3 raster. Then hit "add".  It will tell you it cant find it.  Chose to install it anyway.  I believe this will make it easier to handle printing to pdf.  For printing in autocad I highly reccomend using the "page Setup Manager" you can also use the export option under the "File" menu.

This is all off the top of my head so let me know if it works or needs clarifying. Good Luck!