Haven't fixed this yet, but I did get this post from Steve Werner, in the Acrobat forum:
"found this solution from another Acrobat 9 user:
I've tried cleaning the Safari and User caches to no avail, but in the meantime, have been able to get back to work by logging in as a different user, so I'll keep at the cache-cleaning; if I get it going, will post back.
I have heard these called AutoSuggest or AutoComplete. If you Google
it you'll find a few.built in Flex. I understand they have varying
The www.flextras.com AutoCompleteComboBox will have one coming out
within the next two weeks. We'll be giving an on-line demo of it this
Friday at http://experts.na3.acrobat.com/flextras/ at 1pm EST (