solve on runtime error

Hi really need your help
I am very new in vba
please see below my vba.(excel2003)
I create a vba want to copy a range of data and paste value to other workbook.
it is work fine is file "D:\import.csv" isn't open
but when D:\import.csv is open it get runtime error 1004 PasteSpecial method of Range Class failed. get any clue??

Sub import_SGG()
'
' import_SG Macro
' Macro recorded 7/12/2010 by Fonz Tsui
'Application.CutCopyMode = False
    Range("A2:L50").Select
    Selection.Copy
'Check if import_HSSSG is open
    Dim wb As Workbook
    On Error Resume Next
    Set wb = Workbooks("D:\import.csv")
    On Error GoTo 0
    If wb Is Nothing Then
    Workbooks.Open Filename:="D:\import.csv"
    Else
    Workbooks("import.csv").Activate

    End If

 ActiveSheet.Range("A2").Select
    Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
        :=False, Transpose:=False
End Sub