The problem seems to come from the IAcroAXDocShim. I tried PrintPDV.vi and I got the same error than yours (LV 2009 with Vista).
In the past, this VI worked on this computer but not now. Per curiosity I tried the VI at this link and I have the same error.
I have no idea why it is not working now.
I dont know if this can help, but I was not able to used the library (Windows 7-64, LV2013) until I unblock itextsharp.dll (In Windows 7 or later, you also can right-click the assembly and click Unblock on the General tab to grant an assembly full trust)
Itextsharp DLL is located at:
\Program Files (x86)\National Instruments\LabVIEW 2013\user.lib\Exaprom PDF\DLL