RTMP Streaming Issues

I have a custom flash player that uses the netstream class. It loads videos from an xml document. It's extremely dynamic - loading and unloading pieces of content and video based on user selection as well as where the playhead is in the current video, etc. It works fine when I load the videos from a regular server. However, the videos are long and quite large (7-8 minutes and 80-90 MB) so we are trying to stream them to improve performance. When we move the videos to and AKAMAI streaming server and use RTMP, it completely breaks the experience. Not only is performance terrible, but content randomly shows up at unexpected times, etc. Eventually, it crashes my browser.

I wouldn't know where to even begin posting lines of code for you all to look at. But, any ideas would be appreciated. Could it just be that the bitrate on the videos is too high? Would VBR at 500kbps be too high? Does it need to be CBR?

The bitrate should be ok with RTMP
it almost sounds like the switch from progressive to RTMP is the cause, as in, the player
What format are the videos? flv ? mp4 ?