What server is this for? And does it not give a specific error?
Try checking things such as breaks where they should be, and no spaces after //#CLIENTSIDE, etc.
Also,
PHP Code:
if (this.id != NULL){
'id' is reserved, meaning it is the ID of the object. You can't set it. That may be your problem.
And then, on serverside, timeouts need to be .1 or higher, unlike .05 on clientside.
EDIT:
AHHH!! Tig beat me to it mentioning the space after clientside.