Server Error

After updating to WordPress 3.4.2 I get the error below when I activate Wysija Newsletter plugin.

PHP Warning: is_readable(): open_basedir restriction in effect. File(C:\Inetpub\vhosts\tjnews.gr\httpdocs/wp-content/plugins/C:\Inetpub\vhosts\tjnews.gr\httpdocs\wp-content\plugins\wysija-newsletters/languages/wysija-newsletters-el.mo) is not within the allowed path(s): (C:\Inetpub\vhosts\tjnews.gr\httpdocs\;C:\Windows\Temp\) in C:\Inetpub\vhosts\tjnews.gr\httpdocs\wp-includes\l10n.php on line 339

And the site doesn’t load.

How can I fix it? Can anybody help with this?

Thank you in advance.

http://ww.wp.xz.cn/extend/plugins/wysija-newsletters/