在install页面安装Edusoho，到创建数据库页面（install/start-install.php?step=2）点“创建数据库”时，页面错误代码：500

查看/var/log/apache2/edusoho_error.log:

[Fri Aug 07 09:35:39 2015] [error] [client 183.250.*] PHP Warning:  preg_replace(): Compilation failed: this version of PCRE is not compiled with PCRE_UTF8 support at offset 0 in /usr/share/apache/edusoho/vendor/symfony/symfony/src/Symfony/Component/Yaml/Parser.php on line 571, referer: http://123.57.*/install/start-install.php?step=2
[Fri Aug 07 09:35:39 2015] [error] [client 183.250.*] PHP Warning:  preg_match(): Compilation failed: this version of PCRE is not compiled with PCRE_UTF8 support at offset 0 in /usr/share/apache/edusoho/vendor/symfony/symfony/src/Symfony/Component/Yaml/Parser.php on line 58, referer: http://123.57.*/install/start-install.php?step=2
[Fri Aug 07 09:35:40 2015] [error] [client 183.250.*] PHP Fatal error:  Uncaught exception 'Symfony\\Component\\Yaml\\Exception\\ParseException' with message 'The YAML value does not appear to be valid UTF-8.' in /usr/share/apache/edusoho/vendor/symfony/symfony/src/Symfony/Component/Yaml/Parser.php:59\nStack trace:\n#0 /usr/share/apache/edusoho/vendor/symfony/symfony/src/Symfony/Component/Yaml/Yaml.php(67): Symfony\\Component\\Yaml\\Parser->parse('parameters:?   ...', false, false)\n#1 /usr/share/apache/edusoho/web/install/start-install.php(322): Symfony\\Component\\Yaml\\Yaml::parse('parameters:?   ...')\n#2 /usr/share/apache/edusoho/web/install/start-install.php(152): _create_connection()\n#3 /usr/share/apache/edusoho/web/install/start-install.php(20): install_step3()\n#4 {main}\n  thrown in /usr/share/apache/edusoho/vendor/symfony/symfony/src/Symfony/Component/Yaml/Parser.php on line 59, referer: http://123.57.*/install/start-install.php?step=2

重新编译了pcre，支持utf-8后，发现仍然报错。

求助