Just replied to your "unable to run Project" post. Should've started here first
Myriad Semibold is likely the cause of the problem here. In this Beta, there are some known bugs with correctly importing fonts that are not bold, italic or a combination of the two. Fonts like Myriad Pro Semibold Condensed usually end up importing with the wrong attributes in your MXML code, or cause an improper missing font error. This will be fixed by the next Beta. Sorry if the content you downloaded for the tutorial includes a problematic font. Let me know if this was the case and we'll ask the author to update the tutorial's source files.
To edit text that you imported, just right-click the text on the artboard and choose Edit In Illustrator. This will launch Illustrator where you can make edits. Then hit File>Save, confirm the warning dialog that AI shows and close the doc there. Return to Catalyst and choose to accept your changes.
I had a feeling, so I went back and change my type to be either Myriad Bold
or Myriad regular, and it works now.
Glad to hear this is a known bug and is being looked into.
The 'formatted text ... edit in Illustrator' message you're seeing is a limitation of this beta. You can look forward to much-improved text editing features in the next public beta of Flash Catalyst.