Try:
SELECT distinct 'true'
from ORDR T0
JOIN OCRD T1 ON T1.CardCode=T0.CardCode
where T0.CardCode=$[$4.0.0] and T1.Creditline - T1.balance<$[ORDR.DocTotal.number] and T0.groupnum !=1
Try:
SELECT distinct 'true'
from ORDR T0
JOIN OCRD T1 ON T1.CardCode=T0.CardCode
where T0.CardCode=$[$4.0.0] and T1.Creditline - T1.balance<$[ORDR.DocTotal.number] and T0.groupnum !=1