This error message is a result of you having selected more files than you have purchased an activation number for.

The solution is to return to the file selection area, look at the selected file details and see how much data you've selected to recover, compare that to your available quota, and then reduce the amount of data selected to be the same, or less than, the amount of quota you have available.

The other option is to use the MY ACCOUNT area to upgrade/modify your Activation Number.