Having issues with fastcgi php handler

well i had this problem for a while some of my add ones don't seem to work well with this and also i am using user friendly URLs with the htaccess mod re write rules that the xenforo installation came with i modified it a bit to my own needs as in i added more re write rules but when i went from suphp to fastcgi my site started to run faster and smoother but also started up some issues.

i am not 100% where the fastcgi.conf is i know where php.conf is and where all my Apache conf files are.

i am using php 5.4.x

some of my add ones that use CGI have issues such as waindigo's user upgrades add one i have contacted him several times and he said it configuration on my server. i know other site suffers the same issue but they havent fixed it on there and i haven't figured out what is wrong:

so is there any proper documentation on how to properly configure xenforo to with with fastcgi? any settings/files need to be edited?

and the errors i get from some add ones are issues with magic magic fatel error:
"Fatal Error: Call to undefined method"

also issues with user upgrades add one giving me errors such as this:

i believe that when a user tries to buy something they press on the buy link but the link doesn't generate properly and it doesn't include the sellers email. therefore giving an error i think it a fastcgi mis configuration some where but i not sure how to fix this.

this what i have in my forums folder well a peace of it i wont show the rest due to security reasons:

#The top of your .htaccess file
ServerSignature Off
RewriteEngine On
IndexIgnore *

# Protect your .htaccess file
<Files .htaccess>
        order allow,deny
        deny from all

<Files admin.php>
AuthType Basic
AuthName "Username and password required"
AuthUserFile /home/unkn0wn/.htpasswd2
Require valid-user

#    Mod_security can interfere with uploading of content such as attachments. If you
#    cannot attach files, remove the "#" from the lines below.
#<IfModule mod_security.c>
#    SecFilterEngine Off
#    SecFilterScanPOST Off

ErrorDocument 400 default
ErrorDocument 401 default
ErrorDocument 403 default
ErrorDocument 404 default
ErrorDocument 500 default

<IfModule mod_rewrite.c>
    RewriteEngine On

    RewriteCond %{HTTP_HOST} ^www.portalcentric.net/forums$ [NC]
    RewriteRule ^(.*)$ http://portalcentric.net/forums/$1 [R=301,L]

    #    If you are having problems with the rewrite rules, remove the "#" from the
    #    line that begins "RewriteBase" below. You will also have to change the path
    #    of the rewrite to reflect the path to your XenForo installation.
    RewriteBase /forums

    RewriteCond %{REQUEST_FILENAME} -f [OR]
    RewriteCond %{REQUEST_FILENAME} -l [OR]
    RewriteCond %{REQUEST_FILENAME} -d
    RewriteRule ^.*$ - [NC,L]
    RewriteRule ^(data|js|styles|install) - [NC,L]
    RewriteRule ^.*$ index.php [NC,L]
now some one told me i need to have the htaccess file as htaccess.txt not .htaccess as the hidden format which i have always had

also a friend told me to do this but i don't understand any of this:

[23/02/2014 9:58:06 pm] .:: TeOzSec ::.: location /xf/ {
try_files $uri $uri/ /xf/index.php?$uri&$args;
index index.php index.html;

location /xf/internal_data/ {
location /xf/library/ {

location ~ \.php$ {
try_files $uri =404;
fastcgi_param   SCRIPT_FILENAME $document_root$fastcgi_script_name;
include         fastcgi_params;
[23/02/2014 9:58:31 pm] .:: TeOzSec ::.: Same thing again, replace /xf/ with /forums/
[23/02/2014 9:59:20 pm] .:: TeOzSec ::.: Then rename .htaccess to htaccess.txt and see if that makes a difference