I’m on a Mac — and had the same issue. I went a little nuts with the advice I found on the web — created a private folder for Spotlight (System Preferences / Spotlight / Private / + folder), ran disk utilities from the Install disk, re-installed AE 7, etc. — losing many hours of sleep over the course of one night with a project deadline looming. I was on the verge of putting my fist through the screen or spending a small fortune troubleshooting with Adobe tech support when I thought “I know — I’ll try something that’s completely unrelated and will have no effect whatsoever.” I disabled my firewall and anti-virus autoprotect. Export to SWF worked like a charm.