Is this a frame rate problem or am I exporting it wrong?
Possibly neither. I have seen similar effects when uploading videos to my own web site, which are NOT reencoded. It may be a result of the streaming, or the Flash player. For my own work, the mistiming is not that critical, so I have never investigated the cause.
Hate to bring up an old thread, but this is EXACTLY the same type of issue I am always having, and rather than be accused of not doing a search, I thought that I'd reply to this and see if any can give some insight.
I'm in the exact same situation where the type of edits that I do are critical in syncing audio and sfx to visual cues in the video. As the OP mentioned, I spend countless hours getting things just right on the Premiere timeline, only to have things be not quite right on export...regardless of format it seems.
The bigges then I'm thinking is the root cause is the fact that many audio sources are different. Most music from CDs or online are in 44kHz whereas default sequences in Premiere are in 48kHz, as well as audio from video cameras.
It's really difficult to understand what is the "proper" workflow when working with 48kHz and 44kHz to ensure that WYHIWYG (what you hear is what you get), on export.
Is there anyone that can explain or point in the right direction to solve this issue?