[ic] /admin/index works /admin/ doesn't

[Interchange User]

Hi all,

I have a couple of old catalogs that have been upgraded from the MV 3 
days, currently running on IC 5.01.  When I hit 
http://website.com/cgi/catalog/admin, I get page not found.  When I go 
to http://website.com/cgi/catalog/admin/index or 
http://website.com/cgi/catalog/admin/login, I get login screen.  Can 
anyone tell me why and what the fix is so that the first URL will work? 
  Obviously this is not a big deal, but I'm curious as to why it works 
(or doesn't work) like this.

Thanks!

Peter