Case Sensitivity Ajax Popup

I have a field that uses the Lookup Wizard to create an Edit Box with Ajax Popup. I have added $ajaxSearchStartsWith = false; to AfterAppInit and that works great to make sure I can search on any text. The problem is that the search functionality is case sensitive and I'm not sure how to turn that off. For example, if I type 'computer' but the only record with that word has a capital 'C' (Computer), the search box won't return any result. Any idea why this might be happening? Also, when I enter something in the box that is not in the list, the box turns red (which is great). Is there any way to put a little message above/below the box which would provide an error message (say 'Not in List')?

Thanks for any help or ideas.