Htaccess problem

My site provides user pages at domain.com/username

My problem is I need a different page for domain.com/index or domain.com/aboutus etc.

I really need a "dynamic" username rule with an exclude pages rule I guess.

here is my htaccess code which gives a 500 error

Options +FollowSymlinks
RewriteEngine On

DirectoryIndex index.html index.php

ErrorDocument 404 /slap/pagenotfound
ErrorDocument 403 /slap/pagenotfound
ErrorDocument 401 /slap/pagenotfound
ErrorDocument 500 /slap/pagenotfound

#index
RewriteRule index.html index.php

#index
RewriteRule ^home$ index.php
############ this script use to redirect site to the provided url #############
#RewriteRule ^home$ http://slapgroups.com/index.php [L, R=301]

#nopage
RewriteRule ^pagenotfound$ nopage.php

#Regitration
RewriteRule ^register/createaccount$ userregistration.php

#Regitration Confirmation
RewriteRule ^register/accountconfirmation$ registrationconfirm.php

#Activation Regitration
RewriteRule ^accountactivation/([a-z,\_,A-Z,\_,\-,0-9]*)/([a-z,\_,A-Z,=,\_,\-,0-9]*)$ registrationactivation.php?UsercontactID=$1&AccountId=$2

#after login
RewriteRule ^user/main$ after_login.php

#Payment Detail
RewriteRule ^user/myaccount$ useraccount.php

#Logout
RewriteRule ^user/logout$ logoutuser.php

#creategroup
RewriteRule ^start/creategroup$ http://slapgroups.com/start/creategroup [R=301]
#RewriteRule ^start/creategroup$ http://localhost/slap/start/creategroup [R=301]

#Forgot Password
RewriteRule ^user/forgotpassword$ http://slapgroups.com/user/forgotpassword [R=301]
#RewriteRule ^user/forgotpassword$ http://localhost/slap/user/forgotpassword [R=301]

#Login
RewriteRule ^login/userlogin$ http://slapgroups.com/login/userlogin [R=301]
#RewriteRule ^login/userlogin$ http://localhost/slap/login/userlogin [R=301]

#Remove account
RewriteRule ^account/remove$ removeuseraccount.php

#Send an email page
RewriteRule ^message/?$ contacttouser.php [QSA]

#Report any site user page
RewriteRule ^abuse/([0-9]*)/?$ reportsiteuser.php?reportUserID=$1 [QSA]

#CMS FIND FRIENDS PAGE
RewriteRule ^find/friend$ http://slapgroups.com/find/friend [R=301]

#group Add Discuss page
#RewriteRule ^([a-z,\_,A-Z,\_,\-,0-9.][^user/myaccount|home|pagenotfound|register/createaccount|accountactivation/([a-z,\_,A-Z,\_,\-,0-9]*)/([a-z,\_,A-Z,=,\_,\-,0-9]*)|user/main|user/myaccount|user/logout|start/creategroup|user/forgotpassword|login/userlogin|message/?|abuse/([0-9]*)|find/friend]*)/?$ memberspersonalinfo.php?members=$1 [QSA]

RewriteRule ^([a-z,\_,A-Z,\_,\-,0-9.][^user/myaccount|home|pagenotfound|register/createaccount|user/main|user/myaccount|user/logout|start/creategroup|user/forgotpassword|login/userlogin|find/friend|(abuse/([0-9]*)/?)]*)/?$ memberspersonalinfo.php?members=$1 [QSA]

#RewriteRule ^members/([a-z,\_,A-Z,\_,\-,0-9.]*)/?$ memberspersonalinfo.php?members=$1 [QSA]

 

All the rewrite rules seem to be correct , but some of them may be not supported because of the Apache configuration. You can rename the .htaccess file into .htaccess1 for example and in case 500 error won't appear, then some of the rules are incorrect.

You can comment the .htacess file one after another and see which of Rewrite rules are causing the site error.