我想备份数据库，代码如下：
Private Sub bf_Click()
MsgBox "请插入备份盘", , "复制"
Dir$ ("a:\")
FileCopy "C:\My Documents\data.mdb", " c:\temp.mdb"
If Dir$("a:\data.mdb") > "" Then Kill "databak.mdb"
compactdatabase "c:\temp.mdb", "a:\databak.mdb"
Exit Sub
End Sub
这段代码，哪里出错了？请大家帮帮忙！