Seems odd that a program path would include Files folder. Was that forward slash a typo?

PDF should be opened by whatever program is designated as default for PDF files without having to specify exe location. Example from my Access VBA:
Dim wsShell As ObjectSet 
wsShell = CreateObject("WScript.Shell")
wsShell.Run Chr(34) & Me.tbxLink & Chr(34)
What app are you running this code in?