Error when installing plugins

Hello,

I am working on this site http://www.socialface.com.au/blog and receive this error when searching for plugins inside admin dash:
An unexpected error occurred. Something may be wrong with WordPress.org or this server’s configuration. If you continue to have problems, please try the support forums.

Strangely enough, it only happens intermittently. It also happens to other users in wp-admin.

Any assistance would be much appreciated.

Thank you.