Now i know what the problem are ... its the following section in Init.php that disables all neccessary variables for the OakGallery. Is it "safe" do disable it ?
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// ################################################## ###########################
// set which variables can pass through globals filter
$_allowedvars = array(
'GLOBALS', // of course

'_GET', // }
'_POST', // } system variables
'_COOKIE', // }
'_REQUEST', // }
'_SERVER', // }
'_ENV', // |
'_FILES', // }
'specialtemplates', // special templates from datastore table
'globaltemplates', // used for template cacheing
'actiontemplates', // templates for specific script actions
'phrasegroups', // phrase groups (in addition to 'global')
//'actionphrases', // phrase groups for specific actions
'noheader', // used to suppress the default vB headers
'nodb', // suppress database connection
'nozip', // suppress gzipping
'steptitles', // step titles for upgrade scripts
'pagestarttime', // microtime() from top of page
'_allowedvars', // this array :-)
'___db_user', // lycos has special variables
'___db_host', // lycos has special variables
);