Getting error while trying to implement lookup table.

lookup-error.png

I have two source file "CUSTOMER_ATTR_SOP_RD_FILE" & "KNVP_RD_FILE" , both are .csv file in my local system. I want to copy the data of column NAME1 of "CUSTOMER_ATTR_SOP_RD_FILE" into taget table's NAME1 but the condition is i want to copy only those data form the NAME1 column which corresponding KUNNR(custid) matches with the KUNNAR(custid) of the KNVP_RD_file. While doing this i got an error. I have attached the screenshot of the error with my qs.Plesde suggest me the solution.

Thanks in advance.