Well, let's keep trying.
If I'm in Word, and I want to send the word "hello" to Excel, I can use:
Sub SendThem
AppActivate "Microsoft Excel"
DoEvents
SendKeys "hello"
End Sub
For me, this brings up Excel and types "hello" wherever I am in Excel,
whether that's in a cell or a dialog box or whatever happens to be open.
One key here is the DoEvents call -- this allows Windows to actually give
the other app the focus BEFORE doing the SendKeys, otherwise, it just sends
"hello" to my own app (Word).
Does the addition of DoEvents help at all?