If you are using a harmony, and you click a button once, and flirc is responding to quickly, please try the following.
Fire up the harmony software and go to Devices.
Then click on "Media Center responds to some commands either too many times or only occasionally"
Then change the current setting, which is most likely at 3, to 0.
If that didn't work, please leave the settings, and try changing the interkey delay to 5, as mentioned in this article.