Yes, the text was rasterized.
I was exporting as a Canopus DV AVI file – 720×576 (16:9).
I’ve found that by exporting as a Quicktime movie it eliminates the problem with the graphics, but then when it’s almost finished it says “Error compiling movie: Unknown Error”. Argh!
I really need this exported tonight so that I can burn it for a client to view tomorrow morning :/