Please make sure you're using the latest build, I got side tracked and forgot about your bug report until now
we did find some problems with the UTF8 parsing/converting in the previous build and this may or may not be related.
Alternatively you might be interested in knowing that we're working on a Unicode edition of FlashFXP, right now we're in the alpha testing phase and hope to move to beta by the end of the month. If you'd like to become a tester let me know and I can give you access to the alpha release.