Syntax coloring

[Word2]

I wrote this little program for syntax coloring somthing (letters ect).

But It gives me the error "cannot convert Number to integer" With the first case. Can some one help?

Private Sub RichTextBox_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RichTextBox.TextChanged
        Dim source As String
 
        Dim rtb As New RichTextBox ' name rtb as a RichText Box type
        Dim Codearray() As String ' It's the array of text
        Dim currentline As String ' The currentline of Text
        Dim Line As Integer ' Dunno why I can't use somthing smaller ...
        Dim I As Decimal 'Largestest thing
        Codearray = Split(source, vbCrLf) ' split Code array from source at Center Left
        For I = LBound(Codearray) To UBound(Codearray) 'From lower case to uppercase
            currentline = Codearray(I) ' Code array for line
            ' add auto tab
            Select Case Left() ' the left case
                Case "\" ' comments
                    rtb.Text = currentline ' trb on current line
                    rtb.SelectedText = Len(currentline) ' select text
                    rtb.SelectionFont = New Font(rtb.SelectionFont, FontStyle.Italic) ' make her bold!
                    rtb.ForeColor() = Drawing.Color.Gray  'Change color
                    rtb.SelectedRtf = rtb.Text = Chr(10) & Chr(13)
 
                Case "!" ' normal number
                    rtb.Text = currentline ' trb on current line
                    rtb.SelectedText = Len(currentline) ' select text
                    rtb.SelectionFont = New Font(rtb.SelectionFont, FontStyle.Strikeout) ' make her bold!
                    rtb.ForeColor() = Drawing.Color.Purple 'Change color
                    rtb.SelectedRtf = rtb.Text = Chr(10) & Chr(13)
                Case "&" ' Literal 
                    rtb.Text = currentline ' trb on current line
                    rtb.SelectedText = Len(currentline) ' select text
                    rtb.SelectionFont = New Font(rtb.SelectionFont, FontStyle.Regular) ' make her bold!
                    rtb.ForeColor() = Drawing.Color.Green  'Change color
                    rtb.SelectedRtf = rtb.Text = Chr(10) & Chr(13)
                Case "%" ' Small number
                    rtb.Text = currentline ' trb on current line
                    rtb.SelectedText = Len(currentline) ' select text
                    rtb.SelectionFont = New Font(rtb.SelectionFont, FontStyle.Regular) ' make her bold!
                    rtb.ForeColor() = Drawing.Color.DarkRed 'Change color
                    rtb.SelectedRtf = rtb.Text = Chr(10) & Chr(13)
                Case ""
                    rtb.Text = currentline ' trb on current line
                    rtb.SelectedText = Len(currentline) ' select text
                    rtb.SelectionFont = New Font(rtb.SelectionFont, FontStyle.Bold) ' make her bold!
                    rtb.ForeColor() = Drawing.Color.AntiqueWhite 'Change color
                    rtb.SelectedRtf = rtb.Text = Chr(10) & Chr(13)
                Case "(" ' comments
                    rtb.Text = currentline ' trb on current line
                    rtb.SelectedText = Len(currentline) ' select text
                    rtb.SelectionFont = New Font(rtb.SelectionFont, FontStyle.Italic) ' make her bold!
                    rtb.ForeColor() = Drawing.Color.Bisque  'Change color
                    rtb.SelectedRtf = rtb.Text = Chr(10) & Chr(13)
                Case ")" ' normal number
                    rtb.Text = currentline ' trb on current line
                    rtb.SelectedText = Len(currentline) ' select text
                    rtb.SelectionFont = New Font(rtb.SelectionFont, FontStyle.Strikeout) ' make her bold!
                    rtb.ForeColor() = Drawing.Color.Bisque 'Change color
                    rtb.SelectedRtf = rtb.Text = Chr(10) & Chr(13)
                Case "{" ' Literal 
                    rtb.Text = currentline ' trb on current line
                    rtb.SelectedText = Len(currentline) ' select text
                    rtb.SelectionFont = New Font(rtb.SelectionFont, FontStyle.Regular) ' make her bold!
                    rtb.ForeColor() = Drawing.Color.Brown 'Change color
                    rtb.SelectedRtf = rtb.Text = Chr(10) & Chr(13)
                Case "}" ' Small number
                    rtb.Text = currentline ' trb on current line
                    rtb.SelectedText = Len(currentline) ' select text
                    rtb.SelectionFont = New Font(rtb.SelectionFont, FontStyle.Regular) ' make her bold!
                    rtb.ForeColor() = Drawing.Color.Brown 'Change color
                    rtb.SelectedRtf = rtb.Text = Chr(10) & Chr(13)
                Case ":"
                    rtb.Text = currentline ' trb on current line
                    rtb.SelectedText = Len(currentline) ' select text
                    rtb.SelectionFont = New Font(rtb.SelectionFont, FontStyle.Bold) ' make her bold!
                    rtb.ForeColor() = Drawing.Color.Pink 'Change color
                    rtb.SelectedRtf = rtb.Text = Chr(10) & Chr(13)
                    If InStr(1, currentline, "(") > 0 Then
                        rtb.TabIndex = 1
 
                        Dim comment As Long
                        comment = InStr(InStr(1, currentline, ")"), currentline, "*")
 
                        rtb.SelectedRtf = rtb.SelectedRtf & Chr(10) & Chr(13)
                    End If
                Case Else
                    rtb.Text = currentline ' trb on current line
                    rtb.SelectedText = Len(currentline) ' select text
                    rtb.SelectionFont = New Font(rtb.SelectionFont, FontStyle.Bold) ' make her bold!
                    rtb.BackColor() = Drawing.Color.Red 'Change color
                    rtb.SelectedRtf = rtb.Text = Chr(10) & Chr(13)
            End Select
        Next
    End Sub