Hi Shrivas,
You are in a wrong direction. You don't take the KNA1 table for testing purpose. Better to create the 3 fields of Z table. try to use this. I mean your Ztable contains ( Kunnr ,ort01...).
-> desing the screen by using the Ztable
-> create the two normal screens if required or take a single normal screen
-> handle the user commands in PAI ( if enter or save)
If enter call screen 200 ( enter the value again)
-> if save insert zkna1.
-> it should work 
Finally check the demo programs in SCN
