That's really not enough information for us to go on. If you could write down the actual error or take a screenshot and send it to our support team, they can assist you.
Contact us at support@wizard101.com - and when you contact support, please ensure that you give us: ->the account name ->the character name ->any error messages ->as much information about what you encountered as you can
NEVER send us: ->your password ->your full credit card information
The more information you give up front, the faster your issue can be resolved.
This happens to me allot :( I have to uninstall wizard101 then reinstall it and it takes like an hour to wait for all the worlds to load. It just makes me wanna quit