justalice,
Sorry you've been hit by the 90-second rule. It's there to prevent/help prevent spammers. Sometimes it catches the innocent though (as it can be a bit problematic at times; I've been hit by it myself). I find that in that scenario, I copy the test I've typed, and back all the way out of that "post" then loop around and come back to it "fresh" after a minute or two. Then I paste in teh copied text, Post it, and move on.
In a scenario like yours, when you know there's no way your last post was within 90 seconds, you may post a notice here:
http://forums.comodo.com/index.php/topic,1931.msg59031.html#new so that the website team will know. Be sure to include full details (time of last post, time of the attempted post, other conditions, etc), to the extent that you are able. This will help identify any problems, so that hopefully they can get it resolved for all users.
LM