Some Ableton Live users have reported some problems with plugins I have built using Mingw even though they load fine is every other host (and with Live on my machine). Suspecting that it may be a Mingw issue I built the most basic version of the Introjucer's "Hello world" example and sent it to Ableton. They say it doesn't work and so it's a problem of mine not theirs, yet it does work for me and many other users. If anyone out there has a copy of Live installed, would you mind trying these out? I'd really like to know what's happening.
[EDIT] Statically linking to several of the Mingw dlls seems to have fixed things.