Resolution:
When you open any of the GridServer PDF guides with Acrobat, you may receive an error that says

Unable to extract the embedded font [xyz]. Some characters may not display or print clearly.

Most of the guide will be readable, but some characters may be missing.

This error may be due to a damaged PDF, or a known issue with the Adobe Acrobat reader. First, ensure that the PDF has not been damaged (for example, via transfer as an email attachment.) Then, you should either upgrade your version of Acrobat or adjust the regional settings on your computer.