Plugin search returns an error

I have several Wordpress sites.. but only have this problem with the one listed and with this theme. the error page shows

"An unexpected error occurred. Something may be wrong with or this server’s configuration. If you continue to have problems, please try the support forums.

Try again

I have cleared the cache on the WP site and locally..

Also when trying to use the WPMU dev dashboard plugins I get this error when trying to install other plugins..

Downloading install package from

Download failed. Couldn't resolve host ''