On the Aeries Reporting Server, the Wingdings 2 font (wingdng2.ttf) needs to be installed to produce the check mark which displays on certain reports such as Standards Based Report Cards, otherwise, it will display as a "P".
A missing font could be the issue if a checked checkbox is displayed within Aeries, but it displays as a P when the PDF is printed.
Installing the font will translate "P" into a checkmark. This is a free font bundled with many installations of Microsoft Office or Windows.
Here is an example of what a report might look like with the font missing:
Here is an example of what the report looks like with the Wingdings2 font correctly installed, showing the box properly checked:
Note: After installing the font, the Aeries Reporting Service may need to be restarted, or the server may need to be rebooted to apply the change.