[tex-live] Config question

[Gerben Wierda]

I have one symbol in my own metafont file. WIth TL2004 the following 
happens when the system tries to make it automatically:

Running mktexpk --mfmode / --bdpi 72 --mag 1+0/72 --dpi 72 wierda
mktexpk: Mismatched mode ljfour and resolution 72; ignoring mode.
mktexpk: Can't guess mode for 72 dpi devices.
mktexpk: Use a config file, or update me.

Where does this 72 come from??

Thanks,

G