[Typo3-dev] cObj Error when using hook

[Thomas Mammitzsch]

hi list,

i try to use a hook within css_styled_content in typo 3.8.1 with my 
extension. I want to use an own render_uploads() function (in fact i use 
a copy of the original, only some html-rendering will be changed). but 
if i use the _unchanged_ copy of this function in my ext i get this error:

Fatal error: Call to a member function on a non-object in 
D:\xampp\xampp\eclipse\workspace\typo3.8.1\typo3conf\ext\user_fileupload\pi1\class.user_fileupload_pi1.php 
on line 52

i commented out this lines and the error message disappeared:

line 52:
$fileList = $this->cObj->stdWrap($this->cObj->data['media'],$lConf);

line 132:
$out = $this->cObj->stdWrap($out, $conf['stdWrap.']);

i really don't have an idea, why this doesn't work. maybe you can help me?

best regards, Thomas