Can't create customer master data

Dear Experts,

I'm midst of creating new customer master data. I would be able to enter all information except Partner Functions field. I'm getting error when I enter same customer no. EP-ZSR104 as stated below;

Customer EP-ZSR104 is not defined for function SP (table TPAKD)

Message no. F2643

Diagnosis

The account group of the current customer is not defined for the required partner usage.

Procedure

Within customizing, select Sales and Distribution -> Basic functions -> Partner determination -> Define partner functions -> Customer master data -> Environment -> Acct grp assignment. Here you assign the function required to the current account group.

Can anyone assist on this request. TQ

rgds,

nantha