try this it worked for me:
Run Regedit, and go to this key:
HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Security (change
10.0 to 9.0 for Outlook 2000 SP3 or to 11.0 for Outlook 2003)
Under that key, add a new string value named Level1Remove.
For the value for Level1Remove, enter a semicolon-delimited list of file
extensions. For example, entering this:
..mdb;.url
would unblock Microsoft Access files and Internet shortcuts. Note that the
use of a leading dot was not previously required, however, new security
patches may require it. If you are using "mdb;url" format and extensions are
blocked, add a dot to each extension. Note also that there is not a space
between extensions.
