Resinstalling Itunes does not fix the error? It won't let me play my audible books because 'itunes was not installed correctly', so I reinstalled it and it still won't work. I'm lost, any suggestions?

I recently moved my itunes to a new computer. The audible stuff doesn't automatically come up because its not purchased from the itunes store. So I opened the files with itunes on my new computer. It said that I had to authorise my audible account on this computer which I did, but then itunes came up with the following:

'Could not authorise this computer because iTunes was not installed correctly. Please reinstall iTunes.'

So I uninstalled then reinstalled iTunes and it still didn't work, I then did it again and it STILL DIDN'T WORK.

I have absolutely no idea what to do now, so if anyone has any advice it would greatly appreciated.