Hi.

I found an older machine, on which SilverStripe actually works. BTW, with my regular machine machine I cannot even access the online theme demos. All I get is the SilverStripe logo webpage, and that's it.

I attempted to use three other themes, namely highway, natureweb4, and higherground. In all three cases I get an error page instructing me that [Warning] None of these templates can be found: Page.ss, ContentController.ss The error results from
GET /SilverStripe/?stage=Live.

To utilize the other themes I simply change the literal string parameter for SSViewer::set_them('');

I am changing the themes while the work is in progress, i.e. I already completed a good party of the site, using the blackcandy theme.

I also get the same errors, if I attempt to freshly login to the CMS as admin, after setting it to one of the above.
If it's of any relevance, I'm running on XP Pro.

Any ideas?

once you change themes you should only need to do a ?flush=1. Couple other gotchas - make sure the theme folder is all lowercase and without spaces.