Hehe, stranger still ...

This compiled without a hitch (both to .app and .exe) in VFP8/3117:

LOCAL oSeries, myObject
external array oSeries

oSeries=This.Parent.Series

IF oSeries.Count=1
   myObject=oSeries(1)
ELSE
   myObject=oSeries
ENDIF

There was no FUNC oSeries or DIME oSeries[1] or whatever anywhere in the project.