I had the same problem, and was able to resolve it this way. All of these steps might not necessarily be needed, but I'm posting them all anyway. In my case, I was running Windows 7 64-bit, and had just reinstalled iTunes because of stability problems.
First, temporarily disable any anti-virus programs.
1) When installing, I right-clicked on iTunes64Setup.exe, and chose "Run as administrator"
2) I still received the error message, but chose to ignore. I tunes then launched.
3) click the Windows start button (the windows logo on the screen). Right-click on "Computer" and choose "Manage"
4) Click on "Services and Applications"
5) Click on "Services"
6) Find the "Apple Mobile Device" Service from the list, and double-click on it
7) For startup type, choose "Automatic", then click on "Start"
8) Close iTunes, and re-open it.
9) Enable your anti-virus program again.
I hope this helps! Good luck!