Acrobat 8.1.3 requires two double clicks to open a file

Our agency has a VB app that uses adobe to pull up files routinely (for many employees I support they use this app to pull up dozens of documents a day).
Use to be that when you want to pull up a PDF file from the VB app you double clicked once and the PDF came right up. Now you double click and it brings adobe to the forefront (if not already started) or it will just sit there in the background (if adobe was already started before), and then you have to go back to the VB application and double click on the document name again before it will pull up in the Adobe program in a second adobe window. Only staff with the 8.1.3 update have this issue, those with 8.1.2 do one double click and the document comes right up.