There are 2 places that the Apple Application Support folder might be located, depending on the type of operating system you have - 32 bit or 64 bit. See below
Now it is also possible that this folder is hidden, which is a default setting in Windows. The way to reveal it is to go to your C:\Program Files folder in Windows Explorer, left click on Tools at the top of Window and select 'Folder Options'.
Now another Window should open that has 3 headings - General, View, and Search. Select 'View' and scroll down to where it is written 'Hidden Files and Folders', and make sure that SHOW HIDDEN FILES AND FOLDERS is ticked. I'm assuming you have administrator rights. This should now reveal the folders you might not have been finding before. Then follow the instructions below.
There is also another possibility which I have answered fully in this post
I believe that these should get you sorted. Then follow instructions below.
With Windows Explorer, navigate to your C:\Program Files\Common Files\Apple\Apple Application Support folder.
Copy the libxml2.dll that you should find there, navigate to the nearby Mobile Device Support folder, and Paste it in there also.
Restart the programme all should be well
In case that your OS is (64 bit)
1. Open windows explorer, go to location C:\Program Files (x86)\Common Files\Apple\Apple Application Support
2. Copy file "libxml2.dll"
3. Now paste it in the folder C:\Program Files (x86)\Common Files\Apple\Mobile Device Support
4. Restart the programme, it should not display that message, it should be clear.
Good Luck - Let me know how you do.