failed to open stream: Permission denied

After upgrading my server, all guests and members on the website see broken photos (does not appear) all avatars are seen only photos dont.

All My admins on the site this error does not appear they can see all photos

www.toottii.com

http://www.toottii.com/NourSaliba

and noticed on the profile video Block this error appeared for members and guests only:

Warning: file_put_contents(/home/toottii/public_html/plugins/htmlpurifier/standalone/HTMLPurifier/DefinitionCache/Serializer/HTML/4.2.0,2b9b9775a6db24e4e5a6d3607b3f1ba8,1.ser)
 [function.file-put-contents]: failed to open stream: Permission denied in /home/toottii/public_html/plugins/htmlpurifier/HTMLPurifier.standalone.php on line 11232

How can I solve this problem ? maybe i missed something.

Go to plugins/htmlpurifier/standalone/HTMLPurifier/DefinitionCache/Serializer/HTML and clear all files from there then see what happens.

 Great it worked Thank you very much :)