5:
On Error GoTo 6
    Workbooks.Open Filename:=cudir & "\" & "05_май" & "\" & "DSDI905_0516.xls"
6:
On Error GoTo 7
    Workbooks.Open Filename:=cudir & "\" & "06_июнь" & "\" & "DSDI905_0616.xls"
7:
On Error GoTo 8
    Workbooks.Open Filename:=cudir & "\" & "07_июль" & "\" & "DSDI905_0716.xls"