error message when installing new update

I went to go and install the newest updated and half way through it stopped and told me it failed.

so I went to install it again and it went through fine and updated

I went to go and open iTunes and now I am getting this error message

The procedure entry point ADAdPolicyEngine_DidEnterStation could not be located in the dynamic link library iAdCore.dll

I hit okay and then I get the message

iTunes did not install property. windows error 127. please reinstall iTunes

so now it wont let me even open iTunes so I went to the website and manually downloaded.

it says it downloaded and repaired the files but I still continue to get the same error message listed above.

can anyone help??