Either the value that you entered for the unused storage to configure or a value that the system calculated is larger than the available amount. Reevaluate all of the values (percent unused storage to configure, amount in gigabytes, volume quantity, and volume size) and then recalculate. Experiment with calculations to derive a suitable configuration. Make sure to enter only integer values into the storage configuration fields.
Reevaluate and reenter the values in all storage configuration fields, then recalculate.