Theme Bug

I have the version 1.0 of Oblivion installed. There seems to be a bug which stops me from doing the following things:

1. I cannot live preview any other theme

2. I cannot upload the .zip file for the new version, it stays stuck on 1%

3. When I upload the unzipped theme file for the new version via FTP and activate it, I cannot access anything on the site (not even the admin dashboard)… I had to change it back to the original manually via PHPMyadmin.

Finally.. my site seems to be quite slow to load even though I have the best cache plugin installed, do you have any advice for this or is it fixed in the new version?

Please could you advise asap as it is really stopping me progressing with my site.

Kind Regards