endless loop in webkits, may be htaccess conflict - .htaccess

Question

Got flamer script (http://provenlogic.xyz/flamer) installed and configured but start to get problem just in Opera and Chrome (in Firefox and IE works fine).
Here is my installation http://chronogym.com/flamer
The same url causes endless loop in Chrome and Opera and works fine in FF.
First question is how it could depend on browser, because I thought that redirections are driven only by server side.
Another question: when adding something like dd('test'); somewhere in controller even in FF script begins to brake connection instead of showing dumping result.
Project is placed in subdir on server: root/flamer. In root I got other project. I suggest that .htacces from that project can cause problems or conflicting with .htaccess from flamer but can't find out the exact cause.
root .htaccess
ModPagespeed off
RewriteEngine On
RewriteBase /
#Options +FollowSymlinks
############################################
## always send 404 on missing files in these folders
RewriteCond %{REQUEST_URI} !^/(_css|_js|memberarea)/
############################################
## never rewrite for existing files, directories and links
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-l
############################################
## rewrite everything else to index.php
RewriteRule .* index.php [L]
ErrorDocument 404 http://www.chronogym.com
RedirectPermanent /coaching.php http://chronogym.com/2-0-coaching_minceur.html
subdir .htaccess
<IfModule mod_rewrite.c>
<IfModule mod_negotiation.c>
Options -MultiViews
</IfModule>
RewriteEngine On
# Redirect Trailing Slashes...
RewriteRule ^(.*)/$ /$1 [L,R=301]
RewriteEngine On
RewriteCond %{HTTP_HOST} ^www.chronogym.com/flamer/$ [NC]
RewriteRule ^(.*)$ http://chronogym.com/flamer$1 [R=301,L]
# Handle Front Controller...
RewriteCond %{REQUEST_URI} !^/admin
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^ index.php [L]
</IfModule>

Answer 1

Your middle rule is not correct but that would conflict anyway. You need to use RewriteBase if this .htaccess file is in the flamer folder. Have your rules like this.
RewriteEngine On
RewriteBase /flamer/
# Redirect Trailing Slashes...
RewriteRule ^(.*)/$ /$1 [L,R=301]
# Handle Front Controller...
RewriteCond %{REQUEST_URI} !^/admin
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^ index.php [L]