sum(col2 - col3) as newnumber don't work

[Siffleu]

I'm working with a Datadirect 4.10 sql92 v9.1E ODBC driver
from my sql environement I am unable to perform the following :
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[FONT=&quot]'SELECT PIECE, DESC1, SUM(QTE_REQ - QTE_EXP ) AS nbrBO FROM PUB.VTCOMLIG WHERE CD_CIE = 1 AND CD_SUCC = '[/FONT][FONT=&quot]RIV[/FONT][FONT=&quot]'[/FONT][FONT=&quot] AND [/FONT][FONT=&quot](COMM_CL LIKE ''F%'') AND (QTE_REQ > QTE_EXP) AND (A_EXP = 0) AND (DATE_REQ < ''2009-07-10 00:00:00.000'') GROUP BY DESC1, PIECE'[/FONT]

The OLE DB provider "MSDASQL" for linked server "SISCA" supplied invalid metadata for column "NBRBO". The precision exceeded the allowable maximum.

after test, my problem is "[FONT=&quot]SUM(QTE_REQ - QTE_EXP ) AS nbrBO"

I know somes db doesn't like the AS statement, even if I remove it I still have the same error.

QTE_REQ and QTE_EXP are decimal colomns with simples numbers

anyone have an idea ?
I am unable to find doc for my odbc driver since it's dated of 2004
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