Installing our first live Vista machine today we tried transferring the fonts from the old machine. To do this we copied them from the old machine to a network share then tried to install them from the share.  Finding the Install New Font option was a little tricky and involves going into Control Panel (we then switched to Classic View), Fonts, and in the font list we right clicked which gave the Install New Font option.

However, the message it offered was:

The font [fontname] is not a valid font file and cannot be installed

The solution was to copy the fonts across to a local drive first.