I created an App in vs2010 on win 7 for transfering files from one location to another (directory to directory and also Directory to FTP upload).  It is using .net 4 framework.  I also created an installer for it.  When we try to install it on an XP box, it installs but when you click on the EXE it immediately gives the standard Microsoft windows message "'APP' has encountered a problem and needs to close...  tell Microsoft about the problem...  Blah Blah Blah"

The XP box does have .Net framework 4 installed.  is there a .dll or assembly reference that I should be using to be able to get this to work on XP?  Does anyone have any input on this? 

I am not submitting Code as I do not feel that the code is the issue.  I feel that it has something to do with the operating system and the way that it recognizes how the app was built. If that isnt it, is there a way to compile the code in a lower framework version?  This is bugging me out.

thanks, DP