I'm using Firefox 10 and text objects have always appeared, using system or web fonts.
And unless you post a capx so we can reproduce this on our computers, there is nothing to investigate.
How to report a bug
You seem uneasy about posting a capx.
If you want to keep it private, send it to ashleyoef@scirra.com.
Edit: come to think about it, do you try to display some special alphabet/characters in your text ? (like cyrillic, or another "symbols" alphabet like this in our european's eyes)