the following is the source code in class frmpreviewer.cmdOpen.Click() in classlib prevdemo\previever that I have. Do you have a different VCX?

LOCAL lcName
lcName = GETFILE("XFF File:XFF;XML File:XML","Report:","Open",0, "Select a report to open") &&"outf.xff"
IF EMPTY(lcName)
RETURN
ENDIF

LOCAL loSession
loSession=EVALUATE([xfrx("XFRX#INIT")])
thisform.oReport = IIF(AT("XML",UPPER(lcName))>0,EVALUATE([xfrx("XFRX#XML")]),EVALUATE([xfrx("XFRX#DRAW")]))
IF thisform.oReport.openDocument(lcName)
thisform.cntXFRX.reset()
lnRetVal = loSession.SetParams(,,,,,,"CNT")
loSession.setOtherParams(thisform.cntXFRX)
loSession.TransformReport(thisform.oReport)
ENDIF