It's a Windows-only behavior, that in some cases the embedded fonts are not printed to PDF. The reason is that the needed font is not installed to your system. (For more information about installing fonts see Windows Help system.)
If you cannot install the needed font, the way to create pdf with these text is to turn off the Font embedding check box in the Advanced options tab of the Amyuni PDF Converter dialog. This setting can be switched dependig on your fonts installed.
About embedded fonts:
Embedding prevents font substitution of third-party font types when read of print the file. You can embed the entire font or only a subset of the characters.