Can't render to H264 since upgrade

Hi, I recently upgraded to the latest Blender version (I only went from 2.49 to 2.49b), and I get an error “Can’t Initialize Codec” when I try to render a png sequence out to H264 using exactly the same settings as I had success with using 2.49. Settings are as follows:

Bitrate: 6000
Min Rate: 0
Max Rate: 9000
Mux Rate: 10080000
GOP Size: 15
Buffersize: 1792
Mux PSize: 2048

Any thoughts anyone?

A bug report is in your future.