Beth-

>?VARTYPE(ox.Parent) && blows the 'Parent does not exist' error
>?TYPE('ox.Parent') && returns 'U'

I agree with Çetin that TYPE() is safer in this case. My rule of thumb is this. If in my code I'm sure I'll have a variable, but am not sure what type it is, then I'll use VARTYPE(). If there is a good chance the variable doesn't exist yet (as in your case), then I use TYPE(). It's simplistic but I've found it to be reliable.

To add a note to Çetin's post. For objects, one should be careful about checking just whether their type is "O". It's safer to check a property, say "Name", if it will have one, or add !ISNULL() to the check.