after update: broken admin link & styles don't work anym

[amarillo]

hi!
i've just updated my serendipity 0.7 to 0.8beta2.
after all upgrades were made by the PHP "installer" all seemed to work as expected. but after some changes to the plugin list and the selection of a new theme, i faced some problems.
1.) i use the "link to admin page" plugin to gain fast access to the management section. after the update, this link leads to nirvana: http://<my-domain>/weblog/admin
at this adress i get a "404 error"
2.) right after i've switched to a new style, everything was fine. but some browser refreshes later the style was gone an only black text (in default font/size) on an empty white background was left.
i wanted to change back to the old style, but it had no effect.

are these known bugs for this beta?
is there anything i can do, to get back to a working serendipity?
did i do anything wrong?

please help me

[garvinhicking]

1.) This seems to happen because you enabled Apache Errordocs or mod_rewrite URL Redirection, but your server does not support it. Change it back to "None" in Configuration.

2.) See 1.

Regards,
Garvin