Ah, yes... the old "redirect on the first node" problem. The reason that this causes problems is that the compilation check when you save an XSLT is done against the first node in your site. The redirect causes problems in that situation.
It's a known issue, but I don't know if/when it might be addressed. Search codeplex and vote for it if it's there. If not, please add it so it doesn't get lost.
cheers,
doug.
MVP 2007-2009 - Official Umbraco Trainer for North America -
Percipient Studios