you were so close with:
Code:
Dim StrSql As String 
         StrSql = "Update Alter table [BackArc] Add [Remarks] [Memo]"          
CN.Execute StrSql

Now, look at this EXAMPLE (IN THE LINK I SHOWED YOU IN #11):
Code:
StrSql = "ALTER TABLE Customers  ADD COLUMN CustName TEXT 25
can you take it from here? (Wish you had studied that tutorial!)