Truth to say don't have any idea now, but I can try to find something. Does stored procedure returns some set of records? Do you use "Alert when field ROW:COL.." option of the ODBC test? If yes, does the same error appears when option is disabled?
I think I have fixed the problem. The stored procedure was generating a system message before returning the recordset, when I was deleting a #temp table in the code. I have chenged the stored procedure and it is working now.