Thread:Project:Support desk/User Preferences don't offer Gadgets

I installed a local wiki via MoWeS including MW 1.18.0 at 2011-11-28. Then I added several extensions incl. Gadgets. All requirements for Extension:Gadgets should be fulfilled: LocalSettings has require_once. MediaWiki:Gadgets-definition is defined: *Pfeil-hoch|Pfeil-hoch.js MediaWiki:Gadget-Pfeil-hoch.js and MediaWiki:Gadget-Pfeil-hoch are imported. But this gadget is not yet accepted: What do I miss? Are gadgets preserved for the WMF version of MW? If so, which files must be fixed? Do I need a configuration setting? What else? Thanks for help! Juergen
 * Special:Gadgets doesn't contain any gadget.
 * Special:Preferences doesn't show a tab Gadgets.