Why would a hyperlink not work?

I have a client with a very strange problem which I can replicate on several
computers other than theirs. IE will open the website. You can close IE reopen
and go back to the site. However if you click a link to website within a Word
2010 document or Excel spreadsheet IE gives an error that the page can not be
displayed. If you then close IE and Word, reopen IE and try to go to the site it
says page can not be displayed. If you wait apporx 30 min and try again IE will
display the page. But if you reopen Word or Excel, click the link you get the
same error again and IE will not open the page. This issue only happen with this
particular site, no others. The other interesting part is once one computer on
the network errors out no computer on the same network can access the site
either for approx. 30 min.

The same link works fine in Outlook. All
computers are using Windows 7 64.