Site fixing and developing

I need to develop a page instead of the error message that gets displayed when a member performs an action not allowed in his membership?
The new pages shut invite the member to upgrade whit immediate payment facility.

– I get quite a few error messages like this one:
Query:
SELECT `ID` FROM `sys_localization_languages` WHERE `Name`='en' LIMIT 1
Mysql error: MySQL server has gone away

Found error in the file '/home/freeland/public_html/inc/classes/BxDolEmailTemplates.php' at line 31.
Called 'getOne' function with erroneous argument #0.

Look in to this and do a full check up of the site and fix the problems.

Please a quote for this work.