You are not doing anything with the information that there is missing data. YOu could do it like this.
dataFile = Server.MapPath("~/Documents/ids/" & memberno & ".pdf")
dataFile2 = Server.MapPath("~/Documents/MeansTests/" & memberno & ".pdf")
dataFile3 = Server.MapPath("~/Documents/Contracts/" & memberno & ".pdf")
If Not File.Exists(dataFile) Then
txtfileuploaderror2.Text = "ID document is a required field"
txtfileuploaderror2.Focus()
Exit Sub
End If
If Not File.Exists(dataFile2) Then
txtfileuploaderror4.Text = "Means Test is a required field"
txtfileuploaderror4.Focus()
Exit Sub
End If
If Not File.Exists(dataFile3) Then
txtfileuploaderror3.Text = "Copy of Contract is a required field"
txtfileuploaderror3.Focus()
Exit Sub
End If
Rest of update code
But if there is more than one problem you should really let the user know about all of them as soon as possible e.g
dataFile = Server.MapPath("~/Documents/ids/" & memberno & ".pdf")
dataFile2 = Server.MapPath("~/Documents/MeansTests/" & memberno & ".pdf")
dataFile3 = Server.MapPath("~/Documents/Contracts/" & memberno & ".pdf")
Dim ok As Boolean = True
If Not File.Exists(dataFile) Then
txtfileuploaderror2.Text = "ID document is a required field"
txtfileuploaderror2.Focus()
ok = False
End If
If Not File.Exists(dataFile2) Then
txtfileuploaderror4.Text = "Means Test is a required field"
txtfileuploaderror4.Focus()
ok = False
End If
If Not File.Exists(dataFile3) Then
txtfileuploaderror3.Text = "Copy of Contract is a required field"
txtfileuploaderror3.Focus()
ok = False
End If
If Not ok Then
Exit Sub
End If