I've been having quite a bit of trouble getting an MVC2 web application to find the MySQL connector. I am running CentOS 5.
I've installed the DLL into the GAC using the 2.0 version of the tool
$ mono /usr/local/lib/mono/2.0/gacutil.exe -i v2/mysql.data.dll
Installed v2/mysql.data.dll into the gac (/usr/local/lib/mono/gac)
I verify that it updated the GAC:
$ ls /usr/local/lib/mono/gac/MySql.Data/6.3.5.0__c5687fc88969c44d/mysql.data.dll
I get the following error when I run the application:
Failed to find or load the registered .Net Framework Data Provider MySql.Data.MySqlClient
I created a simple command line application described here: http://www.mono-project.com/MySQL, which works under Mono and .NET on my Windows machine, but does not work on my Linux box.
As far as you added to GAC mysql.data.dll, are you sure you're referencing exactly it or maybe MySQL.Data.dll? Linux has case-sensitive file system so references in solution are too.