Thanks for your answer. I have reinstalled my wiki. Now I receive the following error code:
[08a362df8789b85d404df252] /index.php?title=Main_Page&action=submit Error from line 455 of .../Wiki/extensions/DataTable2/includes/DataTable2.php: Call to undefined function wfProfileIn()
Backtrace:
#0 .../Wiki/includes/parser/Parser.php(3888): DataTable2->renderDataTable(string, array, Parser, PPFrame_DOM)
#1 .../Wiki/includes/parser/Preprocessor_DOM.php(1362): Parser->extensionSubstitution(array, PPFrame_DOM)
#2 .../Wiki/includes/parser/Parser.php(2942): PPFrame_DOM->expand(DOMElement, integer)
#3 .../Wiki/includes/parser/Parser.php(1293): Parser->replaceVariables(string)
#4 .../Wiki/includes/parser/Parser.php(443): Parser->internalParse(string)
#5 .../Wiki/includes/content/WikitextContent.php(323): Parser->parse(string, Title, ParserOptions, boolean, boolean, NULL)
#6 .../Wiki/includes/content/AbstractContent.php(516): WikitextContent->fillParserOutput(Title, NULL, ParserOptions, boolean, ParserOutput)
#7 .../Wiki/includes/page/WikiPage.php(2129): AbstractContent->getParserOutput(Title, NULL, ParserOptions)
#8 .../Wiki/includes/page/WikiPage.php(1655): WikiPage->prepareContentForEdit(WikitextContent, NULL, User, string, boolean)
#9 .../Wiki/includes/EditPage.php(2214): WikiPage->doEditContent(WikitextContent, string, integer, boolean, User, string, array, integer)
#10 .../Wiki/includes/EditPage.php(1506): EditPage->internalAttemptSave(array, boolean)
#11 .../Wiki/includes/EditPage.php(652): EditPage->attemptSave(array)
#12 .../Wiki/includes/actions/EditAction.php(60): EditPage->edit()
#13 .../Wiki/includes/actions/SubmitAction.php(38): EditAction->show()
#14 .../Wiki/includes/MediaWiki.php(500): SubmitAction->show()
#15 .../Wiki/includes/MediaWiki.php(294): MediaWiki->performAction(Article, Title)
#16 .../Wiki/includes/MediaWiki.php(861): MediaWiki->performRequest()
#17 .../Wiki/includes/MediaWiki.php(524): MediaWiki->main()
#18 .../Wiki/index.php(42): MediaWiki->run()
#19 {main}