Okay, that's a fairly complicated title up there, so I'll explain the setup that's causing this error first.
I've got a number of related projects set up in Flash Builder. Each project gets its graphical assets from an exported SWC file (or multiple SWC files.) This works fine, but I wanted to create a shared project that contains stuff used across all projects. The first item in there is a screen with a number of clips containing dynamic text fields on them. This screen (and associated assets) are exported to a SWC and then I have written code in the shared project to add functionality to the screen and buttons. I'm using 2 fonts, both are embedded.
Both show up just fine in my test harness, but when I link the shared SWC and src folder (which is required in order to use this code/assets in the other projects) the textfields blank out if I try to set their text properties. If I leave the default text (set in the FLA) it shows up, and the static text fields in the FLA also show up, it's only when I set the text property.
I've tried a number of combinations, including removing embedding, exporting for ActionScript, setting all textfields in the shared project to dynamic, all with no luck. The main project does have the same font embedded, and I've checked that the same glyphs are selected in both the main and shared projects.
I realize this is a rather complicated setup, but I have yet to find a workflow to allow a designer and developer to work on large projects that is better (but I'd love to hear one!)