[Forum] Great solution for eval(base64_decode Virus

[Subah]

Hello everyone,
While i search in the internet i found a great fast solution for this bad virus "eval(base64_decode"
here:
http://hubpages.com/hub/How-To-Remov...4_decode-Virus

i try this code and it fix the problem totally with all .PHP files in my website but there is a small problem i need to fix it manulally the problem is when i use this solution with my forum and it works but it adds a space to my php pages, so i get
"Warning: session_start() [function.session-start]: Cannot send session cookie - headers already sent "
errors..
any chance of fixing the hack to not add space?
i hope from the Expert cooder take a look on the code to fix this small problem

[shutterfreak]

Probably your PHP pages start with an empty line after having run that cleanup script.

This empty line is sent to your browser.

You need to remove that empty line in every PHP file or you'll run into the same problem.

Once you cleaned up your PHP files, protect them by making them read-only.

[Subah]

How can i make them read-only ?
and is there any other way to make this link goes when i run this script ?
as you see there is "Empty lines removed" in the script but i do not know why it is not removed ?
maybe becuase the script is made for wordpress ?