When i click ''Map domain'' button i get the error "domain already mapped&

Hi, i just insalled wpmu domain mapping > i have the subdomain http://subsite.mainsite.com/ and i want to mappit to http://www.newsite.com

When i click ''Map domain'' button i get the error "domain already mapped''

Previously i was using (network enable) "WordPress MU Domain Mapping" plugin. Now is disabled BUT NOT DELETED

Is there a conflict? or a database record problem?

thanx