For years, I have a program that would print pdf files. But if run on a computer with Adobe Reader X it doesn't work.
From my program I do a ShellExecute with a myfile.xfdf as the file name with the 'print' command and '/h /s' parameters. It would fill in fields in the pdf and then print it.
Like I said this has worked for years with previous versions of reader, just not X.
Try disabling Protected Mode in the Preferences of Reader X. This setting is specific to user.