LDAP Automation error automation error -2147463155 8000500d trying to update AD from Excel VBA

AD on Win 2012 R2

I'm working in an isolated sandbox with a test AD server and a Win 7 workstation running Office 2013. I am new to AD and LDAP, but quite proficient in VB and VBA (and C# for that matter).

The automation error I get might have to do with an invalid LDAP reference. That's all I could dig up.
automation error -2147463155 8000500d

The overall objective is to update Active Directory fields using rows of user data in an Excel spreadsheet and VBA. I loop through each Excel Row and get the email address, and then I do a query through ADODB to get the ADsPath of a user with an AD query using email address which is unique:

Set conn = new ADODB.Connection
conn.Provider = "ADsDSOObject"
conn.Open "Active Directory Provider"
Set cmd = New ADODB.Command
Set cmd.ActiveConnection = conn
cmd.Properties("Page Size") = 1000
cmd.Properties("Timeout") = 30
cmd.Properties("Cache Results") = False
cmd.Properties("Chase Referrals") = &H20 Or &H40
cmd.CommandText = "LDAP://DC=mydc1, DC=mydc2,>;(&(objectCategory=person) (objectClass=user) (mail=" & srcEmail & "));ADsPath;subtree"
Set rs = cmd.Execute

If rs.BOF and rs.EOF Then
    ' no AD record returned, so write out an error in the spreadsheet
    wsData.Cells (i, STATUS_COL) = NOTFOUND_ERR
Else
    rs.MoveFirst
    userDN = rs.Fields(0).Value
    Set thisUser = GetObject(userDN)
    ' so far so good, the userDN was returned as follows, and the GetObject function threw no errors:
    'LDAP://CN=mylastname\, Bill, OU=Users,OU=Information Services,OU=Finance,DC=mydc1,DC=mydc2'
    ' Now comes the problem

    thisUser.Put "Employee-Number", wsData.Cells(i, SRC_EMPLOYEEID_COL)    '<<< This throws the automation error

    ' I tried to use a Get just to see if maybe I was able to do a read, but not a write, but it didn't work either

    adEmail = thisUser.Get("email")      '<<< This also throws the same automation error
'
'
'
    thisUser.SetInfo    '<<< I never make it to here

I am at a loss given the fact that the query to return the AdsPath works fine, but it seems the path it returns is invalid.

Thanks in advance for your help.

Bill