That's great information to know. I may have been a bit extreme with deleting content first and not examining keyframes closer. Just wanted closure with this rendering issue.
I've been relying on the tools in Premiere more and more for animation in presentations (light animations - the heavy stuff is done in AE) and this definitely adds a lot of keyframes to my timeline. I'll take a closer look at keyframes next time I get the dreaded "Error compiling movie. Unknown error" warning (and I will get it again).
Thanks,
Len