My best guess and bet would be missing reference of the Javascript file. Based on the link, it might have happened that you too have just referenced the js file which worked in your dev environment.
At times, the relative url are a little different while hosting and thus autocomplete javascript file might be referenced to a wrong location.
I would suggest you to use this tip:
Resolving Paths in a Multi-Folder WebSite[
^] and correct the reference.
For a quick test, try putting the js file in folders above and below the one it is right now...