Do you have any database created for ezp ?
Have you started the mysql daemon / service ? The configuration in your settings/siteaccess/<yoursitename>/site.ini.append math the database name ?
You can find the answer for your problem in this forum.
Please use the "search forum" box: http://ez.no/content/advancedsearch/?SearchText=kernel+50&SearchButton=Search+forum&SearchContentClassID=14
Take a look here, this is a common mistake: http://ez.no/community/forum/install_configuration/error_kernel_50_no_database_connection_could_be_made_the_system_might_not_behave_properly/re_error_kernel_50_no_database_connection_could_be_made_the_system_might_not_behave_properly__9
