ae7 to ae cs3

i just upgraded all of my cs2 apps to the cs3 production premium suite. everything seems to be working fine with one exception. i'm having issues with ae projects that i made in ae 7 when i open them in ae cs3. most of the things work fine. the first thing that i thought was odd was that it said it couldn't find the render plugin "standard 3D" and would substitute it with its default (which is advanced 3d). i'm not sure that's an issue but it's an alert that popped up. more confusing is an issue i'm having with certain movie files. some of them are literally stopping (not ending but just stopping their movement) well before the movie file is supposed to end. i called the same project back up in ae 7 and the movie file worked fine. i played the movie file in quicktime and it played as it should. now, the issue occurs when i open an existing file that was made it ae 7, into ae cs3. if i make a new project in ae cs3 and import that same movie file, it plays fine. so it seems that the issue occurs when opening projects that were made in ae7 into ae cs3. something goofy is happening in the translation. unfortunately, this is no small problem. all of my ae projects were made or worked on in ae 7 which means i can probably look forward to this issue in a lot if not all of my previous projects that i continue to use.

this has nothing to do with missing effects or missing footage. when watching it you would think that the clip has had time remapping applied with a hold key frame, the movie plays then freezes when there should be more movement but there are no effects, time changes or keframes applied.

this is obviously a big issue as it effects all of my ae projects.

has anyone else experienced this? i'm on a power mac g5 dual 2.7 ghz processor, 4gb ram, os 10.4.10

if you have experienced stuff like this and/or have a solution, please let me know.

thanks