The variable, oExcel in this case, has lost scope. If you ran this code from the command window:

public oleapp,oExcel
gfile=getfile("xls")

If !empty(gfile)
    oExcel = createobject("Excel.Application")
    With oExcel
       .Workbooks.Open(gFile)
       .visible=.t.
    EndWith
Endif

You will see that Excel sticks around. Also, your automation code can be simplified a bit...

If you are doing this in a form, one solution might be this:

gfile=getfile("xls")
If !empty(gfile)
    Thisform.oExcel = createobject("Excel.Application")
    With Thisform.oExcel
       .Workbooks.Open(gFile)
       .visible=.t.
    EndWith
Endif

The key is to make sure the variable that holds a reference to the automation server remains in scope. Otherwise, the instance gets destroyed.