Aww, poor Terri. It looks like she really put her heart into the meeting and everyone leaves for a John Travolta lookalike. (She probably also laid out a decent amount of money booking a disco for the meeting, too). Come to think of it, it can't have made Clark feel too flattered to know that a real Clark Kent ranks lower than a Travolta lookalike.
That still leaves one question unanswered. What on earth were they playing? That's a pretty complicated melody (octave range, almost all of it sixteenth notes) for a disco song.