Private Sub munSJBF_Click() 
On Error GoTo ERR_line 
newname = App.Path & "/data/data.cc" 
datapath = App.Path & "/backup/" & Date & " 备份卡.bak" 
FileCopy newname,datapath 
MsgBox "数据已备份到 " & datapath,64,"提示" 
Exit Sub 
ERR_line: 
MsgBox "不能完成数据备份！",48,"运行错误" 
End Sub 

Private Sub munSJHY_Click() 
On Error GoTo ERR_line 
Me.CommonDialog1.ShowSave 
snewname = Me.CommonDialog1.FileName 
sdatapath = App.Path & "/data/data.cc" 
If snewname <> "" Then 
If MsgBox("还原后将覆盖原有数据，确定还原吗?",vbInformation + vbYesNo,"提示") = vbYes Then 
FileCopy sdatapath,snewname ’ 

MsgBox "数据已经成功还原！请重新登陆 ","提示" 
Unload Me 
frmLogin.Show 
Else 
Exit Sub 
End If 
End If 
Exit Sub 
ERR_line: 
MsgBox "不能完成数据还原，请进入系统后未做任何操作时进行！","运行错误" 
End Sub

data  backup 确保这个文件夹存在
先用 if dir("文件夹路径",vbDirectory)<> then 判断下