Cannot Launch URL error

ONe of my patrons is getting the error stating that the URL // Cannot launch, when he tries to open any URL. He is able to search online from EndNote and the Find Full Text works.  (The forum had a long thread about he PDF link giving this error, but this is the URL to a web address that is not working.)

He is using EndNote X4 (but he said it never worked in X3) and XP.

Thanks.