<i>To begin, ensure your forums/clientscript/vbulletin_css directory is chmod 777 so the stylesheet files can be created.</i>
I hope you will NEVER do something like that... open wide your site to hackers.
And you wonder why people post that they got hacked by kiddie scripts that execute inside /tmp dirs...

Just use a prefix anyway - its just good practise.
If you're using XCache, there is no need for any kind of folder permissions - that is only needed if you're using the File caching method.

Thank you great Dismounted, perfect, I will put the prefix in the config.php file and finally do I change the permissions of the folder ? /includes/datastore/datastore_cache.php Right now is 777 but maybe for protection of my forum I have to change that again, if yes please tell me the correct permissions tu put again in that folder.

So this step is very insecure ?? , now I am very worried because TECK told me that. (thank you!)

Because I did it and have the permission in that folder (/clientscript/vbulletin_css) to 777, so I have to change it urgently ?? and also go to my ACP and put NO in the Set "Store CSS Stylesheets as Files option.

Thank you again for all your awesome help.

Directories should be 755, and files 644.

If the server is set up correctly, you can still use "Store CSS Stylesheets as Files".

Thank you for all your Awesome help Dismounted!!!

I will tell today to my Hosting that please install XCache in the server.

One final question, do I have to do the changes in config.php before to the XCache is installed to prevent that my forum go down or I can do it after the XCache is installed in the server ?

Cheers!!

Tahnk you so much Dismounted I have installed XCache and I see my forum with more speed.

I uninstalled the eAccelerator in the server becasue it was caused conflicts with XCache installed.