Use some other server than the opensuse.org one, like http://mirrors.kernel.org/opensuse/<10.3_update_path> or ftp://ftp.crossbowproject.com/opensuse/<10.3_update_path>
Also, this will probably clear up in a few days if you report it as a bug. Finally, if you want to install one program you can do:
suse@root: # yast2 --install VirtualBox
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