We have seen problems develop when printing PDF files in Windows 7. In a lot of cases where the PDF file is known to be good (not corrupted), the print spooler stops. Try these steps and see if it solves your problem.
Try checking the print spooler. Click Start and type services in the Start Search text box. When you see the Services program, right-click on it. Select Run as administrator, enter the password if it asks you for it and click Continue.