Rovers were found guilty of "failing to ensure that their players and/or officials conducted themselves in an orderly fashion" at a regulatory commission hearing on Wednesday.
They have been fined £10,000, £7,500 of which has been suspended until May 31, 2009.
The incident in question involved both sides' reaction to a scuffle between Rovers winger Morten Gamst Pedersen and Newcastle full-back Habib Beye, who were both booked after tangling over a throw-in.
Rovers won the game 1-0 with a last minute goal from Matt Derbyshire.