A resource availability contour cannot go outside the range of the resources earliest and latest availability dates

A resource availability contour

Encountered a problem at one of our customers today Project Server 2010 installation today. In Resource Center when i try and edit a resource's "Latest Available Date" or "Earliest Available Date" i get an error saying:
A resource availability contour cannot go outside the range of the resources earliest and latest availability dates
I experience this error before, but always forget the reason for it.

The reason is that the resource have custom availability defined, this can only be defined in the MS Project client. An indication that the resource has custom availability is also that "Current Max. Units (%)" is grayed out (inactive).

To solve the problem you need to select the resource and open it up in the MS Project client (3 button on the Ribbon). In the client doubleclick the resource name and modify the values in the "Resource Availability" grid to match what you wanted to type in "Latest Available Date" or "Earliest Available Date".

If you don't have MS Project installed you are out of luck.

Note: a third party program could also have modified the custom availability.

For more information also check out this link:
http://office.microsoft.com/en-us/project-help/set-working-times-vacations-and-holidays-for-your-project-HA001224299.aspx