Fatal error: Call to undefined function mb_detect_encoding()
Solution 1:
Install the gd library also.
check this link http://www.php.net/manual/en/mbstring.installation.php
Solution 2:
There's a much easier way than recompiling PHP. Just yum install the required mbstring library:
Example: How to install PHP mbstring on CentOS 6.2
yum --enablerepo=remi install php-mbstring
Oh, and don't forget to restart apache afterward.