When I call the PrivateFontCollection.AddFontFile method in Mono.net It always returns a standard font-family. This bug has already been reported on several websites, but as far
Found this post from google. If it's any consolation, I'm experiencing the same issue with AddMemoryFont (works fine on Windows, mono gives me a generic font.) If it's any consolation, it looks like it's a problem with Mono, and not your code.
Digging through the source, System.Windows.Drawing.PrivateFontCollection is mostly just a wrapper around GDIPlus.GdipPrivateAddFontFile, which itself is a wrapper around fontconfig's FcConfigAppFontAddFile. The reason it doesn't appear to throw any errors is that GDIplus doesn't check for a return value from fontconfig, so it seems like fontconfig isn't able to read the font for whatever reason, but GDIplus doesn't know about it, so neither does PrivateFontCollection.