They say some things don't translate well, and this is a definite example. The yanks haven't even tried to make it their own, just repeating word for word the English version. Same characters, same words, just not the slightest bit funny.
The episode I watched last night was one of my faves, where Simon spews on his girlfriend's little brother. The English version makes me cry with laughter every time, but this USA version just had me thinking WTF?
Americans - leave the English humour to the English. You f*cked up The Office too.