BAPI_BUS2054_CREATE_MULTI error while creating WBS Element

Hi Gurus,

I am trying to create WBS element by using BAPI_BUS2054_CREATE_MULTI

but bapi raise an error that I can not understand.

in return table I got the following error with the error code CJ - 021

" XXXX-YYYY-ZZZZ WBS Element does not exist "

But I try to create already? What does 'Does not exist' mean?

By the way I am using

CALL FUNCTION 'BAPI_PS_INITIALIZATION'. before using BAPI_BUS2054_CREATE_MULTI

thanks in advance, it is an very important

Mehmet Ali