Oracle 7 Query

Within a VS 2003 BI project, I can create a parmeterized query against an Oracle 7 database by using a ? for the parameter(s).
Example:
SELECT LTrim(RTrim(SWO_ISS.REF)) ACCT, CUS_LOC.NAME CUSTOMER,
SWO_ISS.TRAN_DATE, SWO_ISS.ITEM, ITM_DESC.ITEM_DESCRIPTION, SWO_ISS.QTY, LSTPRC.AMT
FROM MYDB.SWO_ISS, MYDB.CUS_LOC, MYDB.ITM_DESC,
(SELECT LP.ITEM, LP.REVISION, LP.AMT FROM MYDB.LIST_PRC LP
WHERE LP.EFFEND > SYSDATE) LSTPRC
WHERE SWO_ISS.REF = CUS_LOC.CUS_LOC(+)
AND SWO_ISS.COMP_ITEM = ITM_DESC.ITEM(+)
AND SWO_ISS.COMP_ITEM = LSTPRC.ITEM(+)
AND SWO_ISS.COMP_REV = LSTPRC.REVISION(+)
AND SWO_ISS.REF = ?
AND SWO_ISS.TRAN_DATE >= TO_DATE(?,'MM/DD/YYYY')
AND SWO_ISS.TRAN_DATE <= TO_DATE(?,'MM/DD/YYYY')

Unfortunately, as soon as the dataset is saved or Layout view is selected the Field List disappears and all of the report objects lose their data binding.
Worse still, if you click the Generic Query Designer button while working with one of these queries Visual Studio will lock up.

This worked at one time and now has me stumped. What may be the cause of the change?