Internal error

[XyEbEyU7J44AAA5pPRYAAAAE] /index.php/User_talk:RolandUnger Error from line 293 of /var/www/wiki/extensions/SyntaxHighlight_GeSHi/SyntaxHighlight.class.php: Class 'Symfony\Component\Process\ProcessBuilder' not found

Backtrace:

#0 /var/www/wiki/extensions/SyntaxHighlight_GeSHi/SyntaxHighlight.class.php(121): SyntaxHighlight::highlight(string, string, array)
#1 /var/www/wiki/includes/parser/Parser.php(3852): SyntaxHighlight::parserHook(string, array, Parser, PPTemplateFrame_DOM)
#2 /var/www/wiki/includes/parser/CoreParserFunctions.php(1086): Parser->extensionSubstitution(array, PPTemplateFrame_DOM)
#3 /var/www/wiki/includes/parser/Parser.php(3383): CoreParserFunctions::tagObj(Parser, PPTemplateFrame_DOM, array)
#4 /var/www/wiki/includes/parser/Parser.php(3106): Parser->callParserFunction(PPTemplateFrame_DOM, string, array)
#5 /var/www/wiki/includes/parser/Preprocessor_DOM.php(1229): Parser->braceSubstitution(array, PPTemplateFrame_DOM)
#6 /var/www/wiki/includes/parser/Parser.php(3262): PPFrame_DOM->expand(DOMElement)
#7 /var/www/wiki/includes/parser/Preprocessor_DOM.php(1229): Parser->braceSubstitution(array, PPFrame_DOM)
#8 /var/www/wiki/includes/parser/Parser.php(2921): PPFrame_DOM->expand(DOMElement, integer)
#9 /var/www/wiki/includes/parser/Parser.php(1277): Parser->replaceVariables(string)
#10 /var/www/wiki/includes/parser/Parser.php(451): Parser->internalParse(string)
#11 /var/www/wiki/includes/StubObject.php(111): Parser->parse(string, Title, ParserOptions, boolean, boolean, integer)
#12 /var/www/wiki/includes/StubObject.php(137): StubObject->_call(string, array)
#13 /var/www/wiki/includes/content/WikitextContent.php(329): StubObject->__call(string, array)
#14 /var/www/wiki/includes/content/AbstractContent.php(516): WikitextContent->fillParserOutput(Title, integer, ParserOptions, boolean, ParserOutput)
#15 /var/www/wiki/includes/poolcounter/PoolWorkArticleView.php(144): AbstractContent->getParserOutput(Title, integer, ParserOptions)
#16 /var/www/wiki/includes/poolcounter/PoolCounterWork.php(123): PoolWorkArticleView->doWork()
#17 /var/www/wiki/includes/page/Article.php(585): PoolCounterWork->execute()
#18 /var/www/wiki/includes/actions/ViewAction.php(68): Article->view()
#19 /var/www/wiki/includes/MediaWiki.php(499): ViewAction->show()
#20 /var/www/wiki/includes/MediaWiki.php(293): MediaWiki->performAction(Article, Title)
#21 /var/www/wiki/includes/MediaWiki.php(851): MediaWiki->performRequest()
#22 /var/www/wiki/includes/MediaWiki.php(523): MediaWiki->main()
#23 /var/www/wiki/index.php(43): MediaWiki->run()
#24 {main}