Problem in passing parameters to SQL OLE DB provider

I have a clientdataset+provider+adoquery with a SQL statement  with 3
parameters. I set the parameters and try to open the cds and I get the error
"Multiple-step OLE DB operation generated erros. Check OLE DB status value
if available".
This only happens with SQL Server 2000. The same app works with Access 2000.
Any ideas
Yannis