I'm with theorbtwo on this one. Netscape is more strict on its requirements than MSIE — which isn't a bad thing, quite the contrary — and the official standard for URLs says you need to use slashes, not backslashes, for your path separator. See the last line on page 3 of RFC1738 — Uniform Resource Locators (URL), and I quote:

Some URL schemes (such as the ftp, http, and file schemes) contain names that can be considered hierarchical; the components of the hierarchy are separated by "/".

MSIE never should never have accepted your redirection URL. You code line should read:

print $q->redirect( "/Admin" );
[download]

Make sure the case is correct, too.