Sometimes after an update, a workstation will find that when they print they see a number instead of a barcode. This can vary from machine to machine.
You will need to re-install the 3of9 barcode font on your machine. You can download the font .ttf file from the ILLiad downloads page here:
The font download button is down towards the bottom of that page. I'd suggest downloading it and saving it to your desktop and then just double-click to install the font.
This is a direct link to download the font file: