I wrote a fairly complicated workbook with a substantial amount of VBA
in it.
I tested it extensively on Excel XP and found no issues.

I recently put it on a machine that has Excel 2000 and hand numerous
errors.
I tried to save the workbook as an Excel 2000.xls file (which
incidently made the file balloon from 600K to over 1200) and I still
had the same errors. I didn't think that would work, however, I still
need a work around.

Is there an update of some sort I could include with the release so
that I could gurantee compatibility?

The errors seem really arbitrary, I can't really include all of them
but here is an example: (doesn't like the part in the **)

ActiveChart.ApplyDataLabels AutoText:=False, LegendKey:=False, _
HasLeaderLines:=False, *ShowSeriesName:=False,*
ShowCategoryName:=False, _
ShowValue:=True, ShowPercentage:=False, ShowBubbleSize:=False

Thanks,
-Joel