Valid response causes "Subcript out of range" - vbscript

Question

I've got a classic ASP application that contacts a database and receives a valid response but then crashes with
Error Number 9: Subscript out of range
after exiting the IF block the db call is made in. What's odd is that the same code is currently working in production. As far as I can tell they're configured identically (but I suspect there's a subtle difference that's causing this issue) and have identical code bases.
What I want to know is:
Where is this array that I'm supposedly attempting to reach a non-existent index of? I don't see it and the error gives no line number. Is there a chance something is not working correctly in the adodb library?
Perhaps this is a common problem having to do with a certain patch and my particular db connection library? Have you had a similar experience?
How do I troubleshoot a problem that doesn't immediately present itself? Should I just start putting troubleshooting statements in the library?
Explanation of what's happening in the code: When the cookie "click" is received err.number is 0. When the cookie "bang" is received the err.number is 9. It then crashes with that error at the end of the IF block.
<%#Language="VBSCRIPT"%>
<% Server.ScriptTimeout = 150 %>
<%
On Error resume Next
%>
<!--#include file="adovbs.inc"-->
<!--#INCLUDE FILE="DBConn.asp"-->
<!--#INCLUDE FILE="ErrorHandler.asp"-->
<%
'Application Timeout Warning
sessionTimeout = 20
advanceWarning = 5
jsTimeout = (sessionTimeout - advanceWarning) * 60000
'If the users session has expired
If Session("USERNAME") = "" or Session("USERNAME") = NULL Then
Response.Redirect("default.asp")
End If
'If the user has just changed their password. Prompt them that it was successfully changed
If Request("changePasswd") = "true" Then
Response.Write("<script language='Javascript'>alert('Your Password Has been Successfully Changed!');</script>")
End If
Dim connection, cmd, objRS, latestDate, lastDateJPMC, firstDateJPMC, lastDateWACH, firstDateWACH, lastDateWFB, firstDateWFB, accountCount
Function calConvertDate(theDate)
Dim yr, mn, dy, dtSplit
dtSplit = Split(theDate,"/")
yr = dtSplit(2)
mn = dtSplit(0)
dy = dtSplit(1)
if Len(mn) = 1 then mn = "0" & mn
if Len(dy) = 1 then dy = "0" & dy
calConvertDate = "[" & yr & "," & mn & "]"
End Function
set connection = Server.CreateObject("adodb.connection")
connection.Open DBConn
connection.CommandTimeout = 60
set connection = Server.CreateObject("adodb.connection")
connection.Open DBConn
connection.CommandTimeout = 60
'Get Earliest & Latest Date in Database
If Err.Number = 0 Then
Response.Cookies("CLICK")=Err.number
Set cmd = Server.CreateObject("ADODB.Command")
With cmd
Set .ActiveConnection = connection
.CommandText = "CIRS_Admin.spGetLatestDate"
.CommandType = adCmdStoredProc
set objRS = .Execute
End With
latestDate = calConvertDate(objRS("latestDate"))
Response.Cookies("latestdate")=objRS("latestDate")
objRS.Close
Set objRS = Nothing
Response.Cookies("BANG")=Err.number
End If

Answer 1

To debug, please add a statement like
Response.Write (objRS("latestDate"))
before the line
latestDate = calConvertDate(objRS("latestDate"))
so you can see if (for example) the date returned from the server has "-" as separator instead of "/" or if an empty value is returned.
After understanding what is causing the problem you can solve it

Answer 2

1.Where is this array that I'm supposedly attempting to reach a non-existent index of? I don't see it and the error gives no line number. Is there a chance something is not working correctly in the adodb library?
This is your array:
yr = dtSplit(2)
mn = dtSplit(0)
dy = dtSplit(1)
What's odd is that the same code is currently working in production. As far as I can tell they're configured identically (but I suspect there's a subtle difference that's causing this issue) and have identical code bases.
May be you have different regional settings?
I strongly suggest to you use better error handling.
Internal Server Error 500 w/ IIS Log