Offhand, no! The possible list of causes is infinitely long. I'll start with the easiest: is your chair close enough to your desk to enable you to reach your keyboard?
Or, on a more serious and hopefully helpful note - what issue are you experiencing, exactly?
The only reasons I could think of not being able to reply is either the thread is closed (it's not, I checked) or that you were trying to post a link (you need ten posts to be able to post links, anti-spam measure).