how to refer back to created browser instance - vba

Question

I create a browser like so, and manually navigate to the web page I need to be. I intend to automatically pull certain elements once I get to the page I need to be on via a seperate macro
Sub Test()
Set CAS = New SHDocVw.InternetExplorer ' create a browser
CAS.Visible = True ' make it visible
CAS.navigate "http://intraneturl"
Do Until CAS.readyState = 4
DoEvents
Loop
This works fine, then I do
Public Sub Gather
Set HTMLDoc2 = CAS.document.frames("top").document
Call Timer1
With HTMLDoc2
.getElementById("tab4").FirstChild.Click
End With
Call Timer2
Dim fir, las, add1, add2, cit, stat, zi As String
Dim First As Variant
Dim Last As Variant
Dim addr1 As Variant
Dim addr2 As Variant
Dim city As Variant
Dim Thisstate As Variant
Dim Zip As Variant
Call Timer2
Set HTMLDoc = CAS.document.frames("MainFrame").document
Call Timer2
With HTMLDoc
First = .getElementsByName("IndFirst")
Last = .getElementsByName("IndLast")
addr1 = .getElementsByName("txtAdd_Line1")
addr2 = .getElementsByName("txtAdd_Line2")
city = .getElementsByName("txtAdd_City")
Thisstate = .getElementsByName("cmb_Add_State")
Zip = .getElementsByName("txtAdd_Zip")
End With
fir = First.Value
las = Last.Value
add1 = addr1.Value
add2 = addr2.Value
cit = city.Value
stat = Thisstate.Value
zi = Zip.Value
'navigate back to start page
With HTMLDoc2
.getElementById("tab3").FirstChild.Click
End With
End Sub
This works the first time, but after the first time, I get "Object variable or with block variable not set" when trying to run the gather() sub again, on a different web page that contains similar information. Any Ideas as to what im doing wrong?

Answer 1

"The error "object variable or with block variable not set" occurs on: Set HTMLDoc2 = CAS.document.frames("top").document the second time i try running Gather()."
This is probably one of three things:
CAS is no longer an object
To check this, set a breakpoint on the line, press ctr+G in the VBA Editor and type ?CAS Is Nothing in the Immediate Window; the result should be False; if it is True CAS is no longer an object
Like Daniel Dusek suggested, make sure CAS.document.frames("top") is an actual element on the page.
To check this, open the webpage you are trying to script, press F12 in Internet Explorer, click on the arrow in the toolbar and click on the "top" frame element in the webpage, switch back to the Developer Tool and look at the line highlighted. Make sure the frame element is named "top".
The HTML hasn't fully loaded when you try to reference the frame element. Set a longer delay or a loop.
i.e. (untested):
Do Until HtmlDoc2 Is Nothing = false
Set HTMLDoc2 = CAS.document.frames("top").document
Loop
Maybe the more important question is why manually navigate to another page? Can't you automate that part of your process too?