What in the world might this be?

I am using the autocomplete plugin succesfully in a Rails 2.3.2 application. However, when I run in firebug, when it first renders, I get the following error, below. Can anyone tell me what on earth might be the cause (and cure?) of this? Thanks, RVince

element is null anonymous(Object name=element)prototyp...249466790 (line 3588) anonymous()prototyp...249466790 (line 3723) anonymous(function(), "channel[channelnote_note]", 1, function()) prototyp...249466790 (line 3708) anonymous()prototyp...249466790 (line 248) klass()prototyp...249466790 (line 51) uplog?update=UpLogBody()uplog?up...UpLogBody (line 175) [Break on this error] var method = element.tagName.toLowerCase(); \nprototyp...249466790 (line 3588)