"Registration denied, this forum runs an active policy of not allowing spammers. Please contact us via the "Contact Us" page
link if you believe this is in error"
This error means that website is using an anti-SPAM plugin/module to prevent SPAMmers to use the website.

Such plugins/modules usually using an third party anti-spam database http://stopforumspam.com/

you can use search field on that website to enter your IP, email address and username to check whether it is listed or not.

If it is listed, try to use different name/email/IP when accessing website which denied you.

Consider why you were listed and if you are sure you can prevent being listed in future, ask STOPForumSPAM to remove you from their database.