After messing with the permissions till I turned blue, i went into plesk and blew away the hosting part, recreated it, copied a fresh install of Serendipity, copied my uploads back, my custom template, and did the serendipity_config_local.inc.php trick to force it to upgrade the database and poof ...

I am trying to upgrade from 0.8.5 to 1.0-beta1, I get 2 permission errors:

/home/content/n/i/k/nikropht/html/ Not writable
/home/content/n/i/k/nikropht/html/templates_c Not writable

However the true path to my files are :
/var/www/vhosts/nikropht.com/httpdocs

a directory listing shows:
[root ...