[RESOLVED] drive box & errors

I have drive box in my form. Selecting drive a: displays run-time error 68 and programm stops. I read about error handling and I want to instead of run-time error shows some msgbox. I tried to put On Error GoTo 0 everywhere: in form_load(), in drive1_change(), in drive1_click() but it doesn`t work. What should I do to make my custom error?

VB Code:

Private Sub Drive1_Change() 
On Error Goto ErrTrap
'code
Exit Sub
ErrTrap:
'error trapping code goes here
End Sub

thanx, I was putting on Error GoTo after function code, but it have to put it before function code