Edgar,

Your code does,

select SIETAB

and the first error is telling you that that alias is not found. The aerrors that follow are most likely becasue the file is not open or selected. Foix the first problem and the others may go away.

One thing you can do is;

IF NOT USED("Sietab")
   SELECT 0
   USE TheTablename AGAIN ALIAS Sietab SHARED
ELSE
   SELECT SIETAB
ENDIF

This will open the table if it is not already open.