Error Geolication

hello

I installed piwik 1.9.3-b7 (base linux redhat 5)
In this version, the GeoIP plugin is deployed directly during installation
I then downloaded the database GeoLiteCity.dat I placed in the directory / appli/projects/piwik/apache_2.2.11/htdocs/piwik/plugins/GeoIP/libs
On piwik interface: settings / Geolocation is impossible to choose a setting: GeoIP (Php) displayed as “broken” or GeoIP (PECL) or GeoIP (Apache) displayed come not installed

There was an error message:
Can not find the mb_internal_encoding function. Please make safe the mbstring extension is installed and loaded (see attached file)

All instructions for configuring GeoIP were followed :

I also have another warning message:

Warning: We’ve detected the old GeoIP plugin. GeoIP integration is now in Piwik core and this plugin is regarded deprecated. New area and city reports will not be Shown while this plugin is loaded. Please disable the plugin and configure GeoIP. If you want your old location data for visits, use the script Described here then reprocess your reports.

Can you help me please

As of version 1.9.2, when the GeoIP functionality became a standard part of Piwik, the GeoLiteCity.dat file has to be in the directory “misc”. You no longer should have a “plugins/GeoIP” directory.

The missing “mb_internal_encoding” function indicates that the PHP system on your server is incorrectly configured or installed. You must contact your server support to have them enable multibyte string support in PHP. This is essential for proper functioning of the UTF-8 character set within Piwik.