Range.find funktioniert iwie nicht.

Sub Häuser_markieren()
Dim i, a As Integer
Dim c As Range
Dim firstAddress As String
For i = 1 To 300
a = Worksheets(2).Cells(i, 1).Value
If Worksheets(2).Cells(i, 1).Value  "" Then
With Sheets("Tabelle1").Range("A1:AP69")
Set c = .Find(What:=a)
If Not c Is Nothing Then
firstAddress = c.Address
Do
c.Interior.ColorIndex = 3
Set c = .FindNext(c)
Loop While Not c Is Nothing
End If
End With
End If
Next i
End Sub