I should add I've been having this issue since yesterday. Is it just that the artifacts have been relocated? Shouldn't there be a mechanism to indicate the artifacts were moved (or removed)? I can't remember what trick Maven uses to accomplish this, but it's confusing that my nexus proxy indicates it is there when viewing the remote index but cannot resolve the artifact.
The URL you are using for the repository is incorrect.
Replace "repositories" with "groups"
There is more information in the wiki: Maven Getting Started - Users