The below code will send the pdf directly to the default windows printer without opening up Adobe Reader. However, you must specify the path to Adobe Reader for lpDirectory. It works with Adobe Reader 6.

DECLARE INTEGER ShellExecute IN "Shell32.dll" ;
    INTEGER hwnd, ;
    STRING lpVerb, ;
    STRING lpFile, ;
    STRING lpParameters, ;
    STRING lpDirectory, ;
    LONG nShowCmd

= ShellExecute(0, "open", "acrord32.exe", " /p /h c:\test\test.pdf", "c:\program files\adobe\acrobat 6.0\reader\", 0)

Actually, I take that back. If there is a registry entry for acrord32.exe then it works without the path. I just tested the below succsfully:

DECLARE INTEGER ShellExecute IN "Shell32.dll" ;
    INTEGER hwnd, ;
    STRING lpVerb, ;
    STRING lpFile, ;
    STRING lpParameters, ;
    STRING lpDirectory, ;
    LONG nShowCmd

llok=ShellExecute(0, "open", "acrord32.exe", " /p /h c:\acordforms\finishedforms\61nc.pdf", "", 0)