Continuity mistake: The second fight between Chazz and Jimmy where Jimmy was looking for a partner skater and Chazz just got fired from, you can see Chazz has no facial hair or 5 o'clock shadow. When the coach goes and talks to them in jail about partnering up and joining couples skate Chazz has full on facial hair.
Factual error: Error in geography: The figure skating competition in Montreal is implied to be taking place at the Olympic Stadium (both from exterior and interior shots). This stadium was built for the 1976 Summer Olympics - it is not a skating facility. The only ice venue of comparable size is the Bell Centre in downtown Montreal - some 20 km away.
Continuity mistake: When they are fighting after they get their medals, Chazz goes for a large punch, and in the next frame, has given Jimmy a headbutt.
Answer: He is credited. In the beginning, the credits read Will Farrell, then Blades of Glory, and THEN Jon Heder shows up.