Hi cher17,
I see that you are having some problems printing from the web on the Mac.
I will be happy to help you.
I would verify and repair the disk permissions on the Mac to see if that will fix the problem.
1. On the Apple menu bar, click Go, click Applications, and then click Utilities.
2. Double-click Disk Utility.
3. Highlight your hard drive/partition on the left.
4. Click Verify then Repair Disk Permissions.
Restart the computer.
Try printing again.
What web browser are you using?
If it's Safari, try using Firefox to see if that makes any difference.
What are you trying to print? (PDF)
Try printing something other then a PDF to see if that is causing this problem.
What operating system are you using? Mac OS X: How Do I Find Which Mac OS X Version Is on My Computer?
Please let me know if you need further assistance.
Thank you for posting on the HP Forums.
Have a nice day.