creating customer emaster error

Hi Guys,

I am new to sap. I have been working on Ecc6.0. on my home pc..Defined and assigned all organizational units in enterprise structure. trying to create a customer master with an assigned sales area. On Execution its giving me an error saying "sales area 1400 01 01 not assigned for customer".

message number F2644.

please let me know where i am doing wrong..

I have also tried with an already defined sales area other than my one but still gives me the same error message.