Exception encountered, of type &quot;Error&quot;<br />
[Zlpx22fhHUyLagdmRKchLQAAABU] /api.php?action=upload&amp;filekey=filekey&amp;filename=Wiki.png&amp;ignorewarnings=1&amp;token=123ABC   Error from line 663 of /homepages/27/d674680421/htdocs/wiki/includes/exception/MWExceptionHandler.php: Class 'FormatJson' not found<br />
Backtrace:<br />
#0 /homepages/27/d674680421/htdocs/wiki/includes/exception/MWExceptionHandler.php(242): MWExceptionHandler::logError()<br />
#1 /homepages/27/d674680421/htdocs/wiki/includes/AutoLoader.php(81): MWExceptionHandler::handleError()<br />
#2 /homepages/27/d674680421/htdocs/wiki/includes/AutoLoader.php(81): require()<br />
#3 [internal function]: AutoLoader::autoload()<br />
#4 /homepages/27/d674680421/htdocs/wiki/includes/api/ApiFormatJson.php(78): spl_autoload_call()<br />
#5 /homepages/27/d674680421/htdocs/wiki/includes/api/ApiMain.php(1571): ApiFormatJson-&gt;execute()<br />
#6 /homepages/27/d674680421/htdocs/wiki/includes/api/ApiMain.php(547): ApiMain-&gt;printResult()<br />
#7 /homepages/27/d674680421/htdocs/wiki/includes/api/ApiMain.php(477): ApiMain-&gt;handleException()<br />
#8 /homepages/27/d674680421/htdocs/wiki/includes/api/ApiMain.php(439): ApiMain-&gt;executeActionWithErrorHandling()<br />
#9 /homepages/27/d674680421/htdocs/wiki/api.php(83): ApiMain-&gt;execute()<br />
#10 {main}<br />