See https://github.com/tedivm/Stash/issues/61

Stack trace: Warning: mkdir() [<a href='/manuals/php5/function.mkdir.html'>function.mkdir.html</a>]: No such file or directory in D:\htdocs\ezp\clients\Haugenbok\forlagshuset\vendor\tedivm\stash\src\Stash\Driver\FileSystem.php line 185
500 Internal Server Error - ErrorException
Stack Trace

in D:\htdocs\ezp\clients\Haugenbok\forlagshuset\vendor\tedivm\stash\src\Stash\Driver\FileSystem.php at line 185 -+
if (!file_exists($path)) {
if (!is_dir(dirname($path))) {
if (!mkdir(dirname($path), $this->dirPermissions, true))

{ return false; }

}
at ErrorHandler ->handle ('2', 'mkdir() [<a href='/manuals/php5/function.mkdir.html'>function.mkdir.html</a>]: No such file or directory', 'D:\htdocs\ezp\clients\Haugenbok\forlagshuset\vendor\tedivm\stash\src\Stash\Driver\FileSystem.php', '185', array('key' => array('cache', '@@default@@', 'user', 'role', 'assignments', 'bygroup', 'inherited/10'), 'data' => array('return' => array(object(RoleAssignment)), 'createdOn' => '1370302363'), 'expiration' => '1370670520', 'success' => false, 'path' => 'D:/htdocs/ezp/clients/Haugenbok/forlagshuset/ezpublish/cache/priv/stash/0fea6a13c52b4d47/25368f24b045ca84/a1e4f174919d040af6d06113d677c9e0/ee11cbb19052e40b/07aac0ca060c23ee/29a7e96467b69a9f/5a93332e29e9b0de/17b32329e5419153/7595822b7b2794a3/a8b43746d096f4c3/7974afede1b81dcb/f3b050372bef406e/4aed156dce11ef30.php'))
at mkdir ('D:/htdocs/ezp/clients/Haugenbok/forlagshuset/ezpublish/cache/priv/stash/0fea6a13c52b4d47/25368f24b045ca84/a1e4f174919d040af6d06113d677c9e0/ee11cbb19052e40b/07aac0ca060c23ee/29a7e96467b69a9f/5a93332e29e9b0de/17b32329e5419153/7595822b7b2794a3/a8b43746d096f4c3/7974afede1b81dcb/f3b050372bef406e', '504', true)
in D:\htdocs\ezp\clients\Haugenbok\forlagshuset\vendor\tedivm\stash\src\Stash\Driver\FileSystem.php at line 185 -+
at FileSystem ->storeData (array('cache', '@@default@@', 'user', 'role', 'assignments', 'bygroup', 'inherited/10'), array('return' => array(object(RoleAssignment)), 'createdOn' => '1370302363'), '1370670520')
in D:\htdocs\ezp\clients\Haugenbok\forlagshuset\vendor\tedivm\stash\src\Stash\Driver\Composite.php at line 107 -+
at Composite ->storeData (array('cache', '@@default@@', 'user', 'role', 'assignments', 'bygroup', 'inherited/10'), array('return' => array(object(RoleAssignment)), 'createdOn' => '1370302363'), '1370670520')
in D:\htdocs\ezp\clients\Haugenbok\forlagshuset\vendor\tedivm\stash\src\Stash\Item.php at line 355 -
...