500 Internal Server Error

I've installed Dolphin 6.1 everything is fine except for Ocra.
I keep getting the "500 Internal Server Error" I tried to delete the content in the .htaccess file, I still got the same "500 Internal Server Error" is there anything else I should try to get Ocra running?

to make it easy here is the content of the .htaccess file if there is anything I should change please help me.

thanks in advance

AddType application/xml .xsl

RewriteEngine On

RewriteRule ^group/(.+)\.htm$   index.php?action=goto&cat_id=$1   [QSA,L]
RewriteRule ^forum/(.+)-([0-9]+)\.htm$   index.php?action=goto&forum_id=$1&start=$2    [QSA,L]
RewriteRule ^forum/(.+)\.htm$   index.php?action=goto&forum_id=$1&start=0    [QSA,L]
RewriteRule ^topic/(.+)\.htm$   index.php?action=goto&topic_id=$1    [QSA,L]
RewriteRule ^user/(.+)\.htm$   index.php?action=goto&user=$1         [QSA,L]

RewriteRule ^rss/forum/(.+)\.htm$    index.php?action=rss_forum&forum=$1 [QSA,L]
RewriteRule ^rss/topic/(.+)\.htm$    index.php?action=rss_topic&topic=$1 [QSA,L]
RewriteRule ^rss/user/(.+)\.htm$     index.php?action=rss_user&user=$1  [QSA,L]
RewriteRule ^rss/all\.htm$           index.php?action=rss_all&sort=      [QSA,L]