Hi Michael,
I don’t think Premiere CS4 ever fully supported AVCIntra, even though it was listed as a preset, unless it came late in the game as an update.
In your case, you are dealing with a wrapped Quicktime file, and no longer native AVCIntra. I would first take a look here and see if the QT to AVCIntra transcoder is able to convert the footage for you. Tjen import it into Premiere again.
Otherwise, you will likely need to find someone with a copy of FCP and convert to a format supported by Premiere. QT Animation, QT Motion Jpe, QT PNG…
Vince Becquiot
Kaptis Studios
San Francisco – Bay Area