There are a number of reasons you may not be able to access a Skill Gaming Region. Please click the following link below for more information: http://wiki.secondlife.com/wiki/Linden_Lab_Official:Second_Life_Skill_Gaming_FAQ#Why_can.E2.80.99t_I_access_a_Skill_Gaming_Region.3F
Please review the Skill Gaming FAQ found in the Knowledge Base link below: https://community.secondlife.com/knowledgebase/english/skill-gaming-in-second-life-r1534/
Note: If you believe you meet all requirements for access, but are still unable to enter a Skill Gaming Region, please try resubmitting your current billing information and re-logging into Second Life as a first step toward troubleshooting.
If you meet all the requirements and are still experiencing access issues, please submit a Support Ticket here: https://support.secondlife.com/