At DreamHost, the allow_url_fopen directive in the php.ini has been disabled for security reasons. You can read more about this, and about various solutions, at the DreamHost Wiki.
By the way. Please try to use the search facility before posting a question. 99 times out of 100, the question has already been answered. This particular issue has been discussed quite extensively.
Simon Jessey | Keystone Websites
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