The advertised application will not be installed because it might be unsafe.

I have quite a number of installs of an appliction at various sites - no
problems. However on one site they are getting the following error
message.:-
The advertised application will not be installed because it might be unsafe.
Contact your administrator to change the user interface option of the
package to basic
In simpleton terms any help on why this is happening and how to sort it??
VB.net 2003.
I have Googled on this and not sure what the problem is. I thought that it
was to do with a previous install as the user states they cannot re-install
or de-install the application. I advised them to use the tool from Microsoft
to de-install, - the msicuu2.exe file with no effect :-

http://support.microsoft.com/default...b;en-us;290301

Many thanks

Paul Bromley