Help required with SQLite syntax (attached db)

[tmighty2]

    Dim cOld As cConnection
    Set cOld = New cConnection
    m_CN.AttachDataBase "D:\backup.db", "old"
    
    m_CN.Execute "UPDATE main.stuff SET " & _
    "main.resultsfrombatchaligner=old.resultsfrombatchaligner," & _
    "main.acatranscriptionforbatchaligner=old.acatranscriptionforbatchaligner," & _
    "main.f0text=old.f0text," & _
    "main.pmtext=old.pmtext " & _
    "WHERE main.rowid=old.rowid"
    
    Debug.Assert m_CN.AffectedRows > 0
    m_CN.DetachDataBase "old"

I am getting the error "Cannot compile SQL-Statement: near ".": syntax error".

What I want to do it restore the value of the columns resultsfrombatchaligner, acatranscriptionforbatchaligner, f0text and pmtext as I had accidentally set them to ''.
No other harm was done to the db, so I wanted to just restore these values using an older backup db.

Thank you for any help as I don't see my mistake.

Thank you.