I am using default Theme and Friends Feature on, had the same Problem but fixed it.
Here is how i fixed it:
I fixed it.
It was an Error with the settings.urlLookup function.
For Example:
jQuery(settings.inputClass,tmp).autocomplete(settings.urlLookup,settings.acOptions);
It was an Error with the settings.urlLookup function.
For Example:
jQuery(settings.inputClass,tmp).autocomplete(settings.urlLookup,settings.acOptions);