I had 0.9.0.12 and I just upgaded to the last stable.

I'm experienceing the folowing problem:
in frontend I get the following message:

The default skin [custom] set for blog [Strem's] does not exist. It must be properly set in the blog properties or properly overriden in a stub file. Contact the webmaster...

... the skin does exist.

in admin, various sections stoped working:
Templates

You can edit any of the following files (provided it's writable by the server, e.g. CHMOD 766)

Directory /var/www/..../html/blogs/skins/custom not found.

: (I've checked the folder is there and the rights and are set as it should be)

...blogs/admin/b2blogs.php?action=edit&blog=5 the page end's abruptly:

<fieldset>
<legend>Default display options</legend>
<fieldset> <div class="label"><label for="blog_default_skin">Default skin:</label></div> <div class="input"><select name="blog_default_skin" id="blog_default_skin">

blogs/admin/b2browse.php?blog=5 the same:

<div class="bContent">
<h3 class="bTitle"><a href="http://www.stratulat.com/hobby/gallery/">AJAX image gallery</a></h3>
<div class="bText">

So.. what has gone wrong with the upgrade?