Open File issues

[Austin25750675w11r]

Question, I am having a problem with the button function within the Prepare Form Tool. What is happening is that I will customize a button to open two specific files within one button, however, while it works great at first after sometime the button will refuse to open anything as if there was no attachment in the first place. What could be causing this issue? Are the files corrupted, or perhaps attempting to open a previously saved over file? 

[Bernd Alheit]

What does you use at the button?