Ben Watson sent them on their way against the Eagles when he broke the deadlock against his former employers just before the interval.
However, Tony Pulis' men fought back and substitute Aaron Wilbraham made an instant impact with his first goal since August 2012 bringing them level.
"Last year with Brentford we had a very good run and we're doing it now with my new club. I'm just enjoying it," Rosler said.
"The FA Cup is something special for me, it's the best cup competition in the world and it's fantastic to be on to the last 16 and, God knows, if we get a good draw at home, we're moving on hopefully."
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