I would also suggest you check those paths - that is a Plesk path that was discontinued several versions back.
Plesk is now 8.1 - that version sounds like 4 or 5!!
If you are still on a really old Plesk - you need to ask your hosting company why. Is it because the server is so old that they can't update (if so then you are suffering) - or is it because they are poor at updating their servers (again you may suffer from old versions of PHP and MySQL)
If not then your paths should look like...
/var/www/vhosts/vhosts/whitneyportalstore.com/cgi-bin/ubb/Members
It is possible that your host has mapped a psa directory to avoid paths from breaking - but as these directories went out of Plesk 2 or 3 years ago (or more) then I would have thought not.
Just a few ideas for you.
(unless another CP is using PSA in their structure, which I very much doubt it)
