Error when updating: "Could not find update source"


I see on the WPMUDev dashboard that there are updates for the following plugins:
WPMU DEV Dashboard, WP Defender, Snapshot, E-Newsletter and Google Maps. When I try to update the plugins I get the error "Could not find update source", what does it mean and what should I do?

I can install plugins from the WPMUDEV but cannot update, I can install and update from the repository without any issues, problem is with updating from WPMUDEV. I tried updating using the normal wordpress plugins page, it did not work and I tried updating the plugins one by one using the WPMUDEV Dashboard plugin, it does not update it throws the error.

What is wrong and how can we fix this? Please help.