>Seems that is the solution, Now there is no error reported.
>
>But now is the question how to read cBuffer. Simply wait wind alltrim(cBuffer) produces fatal error. In fact,
>any wait window after calling function
>
>answer = sdReadDocumentData(@cBuffer)
>
>produces fatal error. Exception code=C0000005

What is the size of cBuffer you use and how do you fill it?