
Steve must have been typing too fast. Yes, he seems to have absent-mindedly mixed INSERT and UPDATE syntax and got stuck in that rut in follow up posts.
Yep. the evils of cut and paste 
Corrected code from post #2:
Code:
Private Sub YourButtonName_Click() 'change to your button name
Dim db As DAO.Database
Dim sSQL As String
Dim Msg, Style, Title, Response
Msg = "Are you sure you want to submit?" ' Define message.
Style = vbYesNo + vbCritical + vbDefaultButton2 ' Define buttons.
Title = "Data Entry" ' Define title.
Set db = CurrentDb
' Display message.
Response = msgbox(Msg, Style, Title)
If Response = vbYes Then ' User chose Yes.
sSQL = "INSERT INTO Table1 ( Field1) VALUES ( '" & Me.TextBox1 & "');"
db.Execute sSQL, dbFailOnError
sSQL = "INSERT INTO Table2 ( Field1) VALUES ( '" & Me.TextBox1 & "');"
db.Execute sSQL, dbFailOnError
sSQL = "INSERT INTO Table1 ( Field2) VALUES ( '" & Me.cmbText1 & "');"
db.Execute sSQL, dbFailOnError
sSQL = "INSERT INTO Table2 ( Field2) VALUES ( '" & Me.cmbText1 & "');"
db.Execute sSQL, dbFailOnError
sSQL = "INSERT INTO Table1 ( Field3) VALUES ( #" & Me.DateBox1 & "#);"
db.Execute sSQL, dbFailOnError
sSQL = "INSERT INTO Table2 ( Field3) VALUES ( #" & Me.DateBox1 & "#);"
db.Execute sSQL, dbFailOnError
sSQL = "INSERT INTO Table1 ( Field4) VALUES ( '" & Me.TextBox2 & "');"
db.Execute sSQL, dbFailOnError
sSQL = "INSERT INTO Table2 ( Field4) VALUES ( '" & Me.TextBox2 & "');"
db.Execute sSQL, dbFailOnError
sSQL = "INSERT INTO Table1 ( Field5) VALUES ( '" & Me.TextBox3 & "');"
db.Execute sSQL, dbFailOnError
sSQL = "INSERT INTO Table2 ( Field5) VALUES ( '" & Me.TextBox3 & "';"
db.Execute sSQL, dbFailOnError
msgbox "Done"
'clear form
Me.TextBox1 = Empty
Me.cmbText1 = Empty
Me.DateBox1 = Empty
Me.TextBox2 = Empty
Me.TextBox3 = Empty
Me.TextBox1.SetFocus
Else ' User chose No.
msgbox "You selected don't Save!"
End If
End Sub