I submited a bug to segue tech support.
Browser Location contents seem NULL to silk when they're not.

My solution was to set up an include file for IE5.0. When I want to run on 5.0 I uncomment a "use..." line in my frame file.
The .inc file has a declaration for Location and a method for verifying the contents. [I should clear the Clipboard when I'm finished, via "Clipboard.SetText()". What I'm showing below has been tested as is.] I guess you'll have to imagine the indent tabs --VerifyLocation() is a method of Location.

[-] window ComboBox Location
[ ] tag "$41477"
[ ] parent Browser
[ ]
[-] VerifyLocation (STRING sExpectedURL)
[ ] STRING sFoundURL
[ ] Browser.SetActive()
[ ] TypeKeys ("<Home>")
[ ] TypeKeys ("<Shift-End>")
[ ] Browser.TypeKeys ("<Ctrl-C>")
[ ] sFoundURL = Clipboard.GetText()[1]
[ ] Verify (sFoundURL, sExpectedURL, "Location has expected URL")