Can anyone tell me why I get error 91 (i.e. Object variable or With block variable not set) for the following code: -

Public Function Method_Three()
On Error GoTo Err_Method_Three

Dim dbs As Database
Dim tdf As TableDef
Dim rst As Recordset
Dim qdfDelete_1 As QueryDef
Dim qdfDelete_2 As QueryDef
Dim strSQL_1 As String, strSQL_2 As String

strSQL_1 = "DELETE [tblTable - Query Collection].* FROM [tblTable - Query Collection];"

strSQL_2 = "Delete [tblTable - Query Collection].[DAO Name] FROM [tblTable - Query Collection] WHERE "
strSQL_2 = strSQL_2 & "(([tblTable - Query Collection].[DAO Name]) Like ""MSys*""));"

Set dbs = CurrentDb
Set rst = dbs.OpenRecordset("tblTable - Query Collection", dbOpenDynaset)
Set qdfDelete_1 = dbs.CreateQueryDef("", strSQL_1)
Set qdfDelete_2 = dbs.CreateQueryDef("", strSQL_2)

qdfDelete_1.Execute dbFailOnError

With dbs
For Each tdf In .TableDefs
With rst
.AddNew
![DAO Name] = tdf.Name
.Update
End With
Next tdf

End With

qdfDelete_2.Execute dbFailOnError

MsgBox "DAO Collection Updated."

Exit_Method_Three:
Exit Function

Err_Method_Three:
MsgBox Err.Description & "The Error is in Driver Number " & tdf.Name
'Resume Exit_Method_Three

qdfDelete_1.Close
qdfDelete_2.Close
dbs.Close

End Function

The code errors on Set qdfDelete_2

The Error 91 is caused by this line in your Err_Method_Three:
MsgBox Err.Description & "The Error is in Driver Number " & tdf.Name

tdf is not set at the time your msgbox runs.

I don't know if the error I got to get to this point is what you are getting but I got:

3078

The Microsoft Jet database engine cannot find the input table or query 'tblTable - Query Collection'. Make sure it exists and that its name is spelled correctly.

to debug change the Error Handler to the following:

Err_Method_Three:
Stop
Resume 0
MsgBox Err.Description & "The Error is in Driver Number " & tdf.Name

The "Stop" will stop your code on an Error so you can use F8 to step. "Resume 0" will take you back to the Offending Code.

The reason you may have received Error 3078 is that you did not have the table "tblTable - Query Collection", which I do have. As far as setting tdf, the whole routine works OK when the line

Set qdfDelete_2 = dbs.CreateQueryDef("",strSQL_2)

is removed. Hence tdf behaves itself at that time. Hence I think the problem lies elsewhere. My own instincts is the SQL statement strSQL_2. The reason that I say that is that I'm not a SQL person.