Knights was captured on camera glaring and shaking his head at the field umpires while they were gathered in the middle of the ground for the three-quarter time break.
The club has also been handed a suspended $5,000 fine for comments Knights made following the match, when he criticised the number of 50m penalties paid against his team.
The AFL wrote to Essendon earlier in the week seeking an explanation for the incidents. Knights responded by apologising.
“On reflection, as a leader of the football club and a leader in the community, I don’t think the actions at three-quarter time befitted that role as a leader,” Knights said at his Tuesday media briefing.
“I definitely shouldn’t have looked out towards the umpires because I have good relationships with those guys, and also in the press conference after the game I raised some isolated incidents or decisions at the time and that’s not the forum [to do that] either.”
This was taken into account when the penalties were handed down on Wednesday.
"To his credit, Matthew has publicly acknowledged that his actions on the day of the game were inappropriate, particularly coming from a senior club leader," AFL football operations manager Adrian Anderson said.
"There is a continuing struggle to retain umpires at a community level and therefore the AFL will continue to stress the importance of appropriate behaviour towards officials at all levels of the game.”
The fines handed down to Knights and Essendon are suspended until the end of the 2011 season.
