I got an error when you pause the game while you win. 
Viewing post in Trogdor for Game Boy Advance comments
What exact screen were you on when you paused the game? The one where it says "LEVEL BEATEN"? The bit where it shows Trogdor in front of the level, enlarged in the center of the screen? The credits sequence where Strong Bad says "congratulations"? Staff credits? High score entry?
Give me as much info as you can, so that I can try and fix this.