unable to display the user selection dialog. (null)

[Katherine]

I have just loaded Windows XP on a notebook. I need to add
another user with permissions other than the default, but
when I click the Add button, I get the following message:

unable to display the user selection dialog. (null)

The same happens when I access the drive via Properties.
Any ideas?

Thanks.

 

[SNUSA]

I have the same problem adding group (user names) *Using
advanced file security

When I attempt to setup file sharing security after right
clicking on a directory and selecting -Sharing &
Security > Security > Add group or user name button I get
the following error:

"Unable to display user selection dialog box. (null)