Oracle Stored Procedures from asp

I'm having some problems calling a stored procedure from an ASP page.
When testing the page I get the error message

"Microsoft OLE DB Provider for Oracle error '80040e14'

Syntax error in {call...} ODBC Escape."

The code I'm using is as follows (names changed to protect the
innocent of course)

With ObjCmd
.ActiveConnection = strExpandConn
.CommandText = "{call Packagename.ProcedureName({resultset
100,det_return})}"
.CommandType = adCmdStoredProc

.Parameters.Append .CreateParameter("Agr_Num", adBSTR,
adParamInput)
.Parameters("Agr_Num") = AgreementNumber

set ObjRS = .execute
end with

Any advice would be appreciated