what is it and what can I do about it?
You can read about it here:
Some applications look at the Panose number to find the font in memory (speed up process) and will often replace it with a similar font (seems dumb to me but what do I know?). If no Panose number is found ( 0000000000 ), it will use Times, Currier, or Arial.
Just insert a number.
There are lots of other possible problems. some applications want to see specific flags set in a font such as Proportional Spacing. Not a Proportional Spaced Font? Sorry, no can do. Erwin or Bhikkhu Pesala can take a look at your font and tell you more than I can.