This is generally caused by an incompatible text format

1. Create a text box on the template screen of exPressit
2. Try increasing the size of your text
3. Try changing the text font to Arial.
4. Then try typing something inside the text box and you should see the standard characters appearing

It then might be worth re-installing the font and trying it again in exPressit as it could be that the font is corrupted in someway.

Lots of free fonts can be downloaded from here