Fatal Error Serializer.php

Hi All .
When trying to upload a video via the member upload option I get the following error.

Fatal error: Directory /var/www/vhosts/mydomain.com/httpdocs/include/htmlpurifier/HTMLPurifier/DefinitionCache/Serializer/HTML not writable, please chmod to 777 in /var/www/vhosts/mydomain.com/httpdocs/include/htmlpurifier/HTMLPurifier/DefinitionCache/Serializer.php on line 160

Any ideas anyone ?

Sorted, did what it asked on line 1. are there any security issue's with chmoding to 777 ?

chmod 777 is required. Not a security issue, 777 folders can be used by hacker, but only when hacker get it. It is impossible to avoid having folders with 777 permissions.

Thanks for the info ;-)