Fatal error & Message "...product wasn't find"

[hartclip]

Hello,

I do not know how to do and I'm really pissed off!
I have 3 problemes it's hard to explain them for me because I'm french so excuse my english.

1 - When I am log (Module BT Login) I have a Fatal error.
2 - When I am not log I have the message : Sorry but the product wasn't find"
3 - When I am not log but I put in the back-end that I don't choose any group user for the product I have the Fatal erro.

VirtueMart 2.0.14
Joomla 2.5.7
SEO are not checked
SEF is checked
Cache is not checked
Template defaut of VM
I use the same configuration of demo VirtueMart

.htaccess with :

• RewriteEngine On
  RewriteBase /
  RewriteCond %{REQUEST_FILENAME} !\.(jpg|jpeg|gif|png|css|js|pl|txt)$
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteCond %{REQUEST_URI} ^(/component/option,com) [NC,OR]
  RewriteCond %{REQUEST_URI} (/|\.htm|\.php|\.html|/[^.]*)$ [NC]
  RewriteRule ^(.*) index.php [L]

Configuration Joomla SEO everything is on ON

I have indulged my client site for Sunday! 3 days that I don't find anything on the subject!
I relly hope that someone can help me beacause I really when keep VirtueMart!

Kind Regards
Edith

PS / Hikashop is installed!