http://www.hydrogenaudio.org/index.php?showtopic=11267&hl=flac+to+mp3

It looks like lamedrop[XPd] doesn't know FLAC.

A mareo action line would be something like this:

flac NONE NONE FullyQualifiedPathToFlac\flac.exe "@source@" --output-name="@dest@"

This would put the flac file in the same dir as the mp3

--Nathan