Whoops! The default skin for your wiki, defined in $wgDefaultSkin as vector, is not available.
Your installation seems to include the following skins. See Manual: Skin configuration for information how to enable them and choose the default.
-  
cologneblue / CologneBlue (disabled) 
-  
modern / Modern (disabled) 
-  
monobook / MonoBook (disabled) 
-  
vector / Vector (disabled) 
-  If you have just installed MediaWiki
 
-  You probably installed from git, or directly from the source code using some other method. This is expected. Try installing some skins from mediawiki.org's skin directory, by:
 
-  Doing this should not interfere with your git repository if you're a MediaWiki developer.
 
-  If you have just upgraded MediaWiki
 
-  MediaWiki 1.24 and newer no longer automatically enables installed skins (see Manual: Skin autodiscovery). You can paste the following lines into 
LocalSettings.php to enable all installed skins: 
wfLoadSkin( 'CologneBlue' );
wfLoadSkin( 'Modern' );
wfLoadSkin( 'MonoBook' );
wfLoadSkin( 'Vector' );
-  If you have just modified 
LocalSettings.php 
-  Double-check the skin names for typos.