as it is a extremely urgent matter for Joomlart that users read the terms of use which can be seen here:
http://www.joomlart.com/joomla_templates_club_faqs/448.html
and more specific read here:
Can I edit or remove JoomlArt Copyright?
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Yes. You can edit or remove the JoomlArt copyright information at the bottom of the template.
You can claim the copyright notice "All right reserved", however the claim on creation of the template, such as:"Designed by Your Company"...are not allowed.
Allowed: Copyright © 2005 - 2006 Your Company. Developed by Your Company Not Allowed : Copyright © 2005 - 2006 Your Company. Designed by Your Company
Which makes this hard to support when you have added this here:
Designed by AfriNIC.net