By default, PowerPoint does not embed your fonts within the saved file. This needs to be enabled within the PowerPoint save settings in order for your fonts to be kept when uploading to SimTutor Author.
This can be easily done by re-saving your Powerpoint, using the following instructions...
1. Go to File -> Options
2. Under "Save" on the left pane, check the box next to "Embed fonts in the file"
3. Click "Ok", and re-upload the PowerPoint into SimTutor Author. The fonts should now be correct!