If an error report is generated when you press the print button, close the document, re-open it, and then choose the print option from the file menu.
If this does not work, reboot the computer and close down all active applications. Press CTRL-ALT-DEL on your keyboard to bring up Windows task manager and then close down all applications in the Applications tab.
Then, open the Safeguard Viewer from the Windows start menu > Programs > LockLizard > Lizard Safeguard > PDF Viewer > View documents, and then from the File > Open menu, open the protected document.
Then choose the print option from the file menu.
Also try printing just a few pages at a time as that will affect the amount of memory consumed.
Printing to postscript drivers is more likely to cause memory problems because postscript drivers do not support compression. Switching to a PCL driver will therefore improve and/or solve the issue.