[Typo3] Extension key "uploads" was NOT loaded!

[ChevronX]

Hi!
 I get the following error message, if I try to open the "Constant Editor" 
for my template:
 >> TYPO3 Fatal Error: Extension key "uploads" was NOT loaded! 
(t3lib_extMgm::extPath)
 I was not able to find in the mailinglist archive or any other locations a 
solution for the problem. I found similar errors from others, but their 
solution to clear the typo3conf-cache is not solving my error.
 Does anyone know how to solve this error?
 Thanks!