Plesk 11 changed the original domain name and now php open_basedir issue

Plesk 11 changed the original domain name and now php open_basedir issue

I am new to Plesk and after going through the setup process and entering
my original domain name (call it domain.com) all was working well. I then
got a new domain name (domain2.com) and updated the record in the Websites
and Domains tab. This was fine, all traffic got routed correctly, however
now php has an issue and whenever I try to use include, I get the error
message (I have 3 domains set up, domain.com was the original, domain2.com
was the new one, domain3.com is just an addition which worked until the
change and the one that causes the include errors):
PHP Warning: include(): open_basedir restriction in effect.
File(/var/www/vhosts/<domain2.com>/<path>/<file>) is not within the
allowed path(s): (/var/www/vhosts/<domain.com>/:/tmp/) in
/var/www/vhosts/<domain2.com>/<path>/index.php on line 3, referer:
http://<domain3.com>/<file>
PHP Warning: include(/var/www/vhosts/<domain2.com>/<path>/<file>): failed
to open stream: Operation not permitted in
/var/www/vhosts/<domain2.com>/<path>/index.php on line 3, referer:
http://<domain3.com>/<file>
PHP Warning: include(): Failed opening '/' for inclusion
(include_path='.:') in /var/www/vhosts/<domain2.com>/<path>/index.php on
line 3, referer: http://<domain3.com>/<file>
Should I just reinstall Plesk and start again? Thanks!