URL Blocked While Doing Bookmark Submission

Hello Friends,
I am having a problem with URL blocked for one of my client's website while submitting bookmark promotion. Kindly let me know what is the reason behind that. And please provide me with the best solution.

Thank You

what is the extension your using for your website? Most of the social bookmarking sites reject because they see it as invalid domain names. If you are using social bookmarking backlinks to influence search rankings, Don't bother because Search engines place very little weight on links which you can place yourself, and most social sites mark user submitted links as nofollow, useless as backlinks. Social sites may be useful for driving traffic, but not for SEO.