[TYPO3-english] Fatal error with module-type extension when upgrading from TYPO3 4.2.9 to 4.4.2

[Jochem Nabuurs]

Jochem Nabuurs wrote:
> Hi list,
> 
> I'm having difficulties with updating a TYPO3 installation from 4.2.9 to 
> 4.4.2
> 
> I've created an extension which is a backend module. With it, users can
> upload certain files. After the update, when I select the module, I get 
> the following error:
> 
> Fatal error: Cannot redeclare xdebug() (previously declared in 
> /var/www/sites/.../html/typo3_src-4.4.2/t3lib/config_default.php:489) in 
> /var/www/sites/.../html/typo3_src-4.4.2/t3lib/config_default.php on line 
> 493
> 
> The function xdebug exists only once in the file, on line 489.
> I think the error occurs because the file is included twice (somewhere) 
> but if that's so, then why are the linenumbers different??
> 
> Maybe it's a dumb question, maybe it isn't.
> Anyway, I hope someone can provide me with some hints because I'm stuck.
> 
> Thanks in advance!
> 
> Jochem

and I've cleared the temporary files (typo3conf/temp_CACHE*) but that 
doesn't seem to help. I don't have the debug extension installed so that 
couldn't be the problem either.