Diego,

D> call it in delphi with the SQLStoredProc component (dbexpres).

A google search shows it's a dbExpress problem.
My experience says dbExpress is no good at all with stored procedures.
I suggest you use plain queries, or try to put together a reproducible
test case and send it to the driver manufacturer (which could be
either Borland or Upscene depending on the driver you are using).

Ciao
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