Xailer & OZ Software

I am putting the following code in the OnChange event of a DBBrowse object:
cSeekVal := "CCIVIL " + ::oDbfDataSetCCivil:IdNo
::oDbfDataSetPlaintiffs:SetScope( cSeekVal, cSeekVal, .T., .T. )
When I run the project, I get the following GPF:
#1: GPF (Code = c00000fd):
Stack overflow
TFOLDER:GETFONT (0)
TFOLDERPAGE:GETFONT (456)
TPANEL:GETFONT (456)
TDBBROWSE:GETFONT (456)
TDBBRWCOLUMN:OFONT (456)
TDBBRWCOLUMN:PAINTDATA (105)
TDBBROWSE:DRAWLINE (265)
TDBFDATASET:CHANGEPOS (1276)
TDBFDATASET:GOTOP (402)
TDBFDATASET:SETSCOPE (1359)
FORM_CCIVILCASES:DBBROWSEPLAINTIFFSCHANGE (2145)
TDBBROWSE:ONCHANGE (0)
TDBBROWSE:DSNAVIGATE (650)
TDBFDATASET:UPDATECONTROLS (1211)
TDBFDATASET:GOTOP (408)
TDBFDATASET:SETSCOPE (1359)
FORM_CCIVILCASES:DBBROWSEPLAINTIFFSCHANGE (2145)
TDBBROWSE:ONCHANGE (0)
TDBBROWSE:DSNAVIGATE (650)
TDBFDATASET:UPDATECONTROLS (1211)
This code is running on a Vista Business operating system.
Any clues as to what is going on? This same scope statement works in the
OnCreate() event.
TIA,
Gary