Problem from Hell (part II)

Okay, I have steps now. I'd hoped to submit this to Adobe as a bug, but it would mean sending the entire project as well, and the client is leery of that. But here are the steps (again, names changed). Note that all the .mxml files described here are applications at the top level of the project.

Flex plug-in version 3.0.214193
Open project

1. Build TestsUnit.mxml, note it succeeds.
2. Set TestsHohoSpecial.mxml as default and build. Note errors (66, none of which make sense).
3. Save original content of TestsHohoSpecial.mxml by selecting all, copying and pasting into the Notepad.
4. Replace contents of TestsHohoSpecial.mxml with contents of TestsHoho.mxml (open TestsHoho.mxml, select all, copy, open TestsHohoSpecial.mxml, select all, paste).
5. Build TestsHohoSpecial.mxml, note it succeeds.
6. Replace contents of TestsHohoSpecial.mxml with its original contents (from the Notepad).
7. Build TestsHohoSpecial.mxml, note that now it succeeds.
8. Set TestsUnit.mxml as the default application, build. Note the same 66 errors.

Okay, so why is the state of step #2 different from step #7? And why is step #1 different from step #8? And can I bill for the time I'm wasting on this without looking entirely incompetent?