MDB means Microsoft Database and it is created by MS Access. If you don't
have Access, you can download a free viewer for any of the Microsoft Office
applications (Access, Excel, Power Point) at http://office.microsoft.com/en-us/downloads/HA010449811033.aspx
I would suggest downloading the Access 2002 viewer first and if that doesn't
do the trick, try Access 2000 or Access 97.