Sounds like you found a solution.
Just adding my 2cents:
I always do this - export frames (.png with transparency in my case) as I have had some codec issues with AVI outputs previously. Then I import the image sequences into Adobe Premiere. It's also nice because I queue up my renders based on how many frames I can render overnight, so in the end I'll have several sets of sequences that make up 1 animation and it's easy to combine them all using the raw frame outputs.
One thing to watch for is your FPS in your animation, versus the FPS in your project file. Premiere and After Effects, I believe, tend to work at 30fps as their default, so if you rendered at 24fps or something other there might be some variation in your playing time.