I compared my file to yours and the only major difference I can find is in the $this->favpet line...here is what mine looks like:
PHP Code:
public function getFavpet(){
if(is_numeric($this->favpet)){
$this->favpet = ($this->favpet == 0)?new Comment("None Selected"):new Link("levelup/click/{$this->favpet}", new Image("levelup/siggy/{$this->favpet}"), TRUE);
}
return $this->favpet;
}
The only difference being the new Image section. Might try changing it just to be sure that's not the issue?