xACT is (was) just calling the command line "metaflac" command. The way cocoa works, though, was converting any unicode arguments I was passing to metaflac. I spent a bunch of time yesterday and this morning to change the way tags are working. xACT no longer call the command line "metaflac" and will read and write the tags directly. i've also added support for album art
need to do some more testing and cleanup tomorrow