[Plugin: W3 Total Cache] Disk enhanced page caching is giving me 500 error page

Hi. i recently got a problem with this great plugin.

when i activate it there is the following message :

Disk enhanced page caching is not active. To enable it, add the following rules into the server configuration file (/home/website/public_html/mywebsite.com/.htaccess) of the site above the WordPress directives . Or if permission allow this can be done automatically, by clicking here: .

when i click autoinstall it gives me a 500 error page. so i have to replace with a ht access file to get my website up again.

what is posibly wrong with it?
this is the htacces file

# BEGIN W3TC Browser Cache
<IfModule mod_deflate.c>
<IfModule mod_setenvif.c>
BrowserMatch ^Mozilla/4 gzip-only-text/html
BrowserMatch ^Mozilla/4\.0[678] no-gzip
BrowserMatch \bMSIE !no-gzip !gzip-only-text/html
BrowserMatch \bMSI[E] !no-gzip !gzip-only-text/html
</IfModule>
<IfModule mod_headers.c>
Header append Vary User-Agent env=!dont-vary
</IfModule>
<IfModule mod_filter.c>
AddOutputFilterByType DEFLATE text/css application/x-javascript text/html text/richtext image/svg+xml text/plain text/xsd text/xsl text/xml image/x-icon
</IfModule>
</IfModule>
<FilesMatch “\.(css|js|CSS|JS)$”>
FileETag None
<IfModule mod_headers.c>
Header set X-Powered-By “W3 Total Cache/0.9.2.3”
</IfModule>
</FilesMatch>
<FilesMatch “\.(html|htm|rtf|rtx|svg|svgz|txt|xsd|xsl|xml|HTML|HTM|RTF|RTX|SVG|SVGZ|TXT|XSD|XSL|XML)$”>
FileETag None
<IfModule mod_headers.c>
Header set X-Powered-By “W3 Total Cache/0.9.2.3”
</IfModule>
</FilesMatch>
<FilesMatch “\.(asf|asx|wax|wmv|wmx|avi|bmp|class|divx|doc|docx|exe|gif|gz|gzip|ico|jpg|jpeg|jpe|mdb|mid|midi|mov|qt|mp3|m4a|mp4|m4v|mpeg|mpg|mpe|mpp|odb|odc|odf|odg|odp|ods|odt|ogg|pdf|png|pot|pps|ppt|pptx|ra|ram|swf|tar|tif|tiff|wav|wma|wri|xla|xls|xlsx|xlt|xlw|zip|ASF|ASX|WAX|WMV|WMX|AVI|BMP|CLASS|DIVX|DOC|DOCX|EXE|GIF|GZ|GZIP|ICO|JPG|JPEG|JPE|MDB|MID|MIDI|MOV|QT|MP3|M4A|MP4|M4V|MPEG|MPG|MPE|MPP|ODB|ODC|ODF|ODG|ODP|ODS|ODT|OGG|PDF|PNG|POT|PPS|PPT|PPTX|RA|RAM|SWF|TAR|TIF|TIFF|WAV|WMA|WRI|XLA|XLS|XLSX|XLT|XLW|ZIP)$”>
FileETag None
<IfModule mod_headers.c>
Header set X-Powered-By “W3 Total Cache/0.9.2.3”
</IfModule>
</FilesMatch>
# END W3TC Browser Cache
# BEGIN W3TC Page Cache core
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^(.*\/)?w3tc_rewrite_test$ $1?w3tc_rewrite_test=1 [L]
RewriteCond %{HTTP_USER_AGENT} (2\.0\ mmp|240×320|alcatel|amoi|asus|au\-mic|audiovox|avantgo|benq|bird|blackberry|blazer|cdm|cellphone|danger|ddipocket|docomo|dopod|elaine/3\.0|ericsson|eudoraweb|fly|haier|hiptop|hp\.ipaq|htc|huawei|i\-mobile|iemobile|j\-phone|kddi|konka|kwc|kyocera/wx310k|lenovo|lg|lg/u990|lge\ vx|midp|midp\-2\.0|mmef20|mmp|mobilephone|mot\-v|motorola|netfront|newgen|newt|nintendo\ ds|nintendo\ wii|nitro|nokia|novarra|o2|openweb|opera\ mobi|opera\.mobi|palm|panasonic|pantech|pdxgw|pg|philips|phone|playstation\ portable|portalmmm|\bppc\b|proxinet|psp|qtek|sagem|samsung|sanyo|sch|sec|sendo|sgh|sharp|sharp\-tq\-gx10|small|smartphone|softbank|sonyericsson|sph|symbian|symbian\ os|symbianos|toshiba|treo|ts21i\-10|up\.browser|up\.link|uts|vertu|vodafone|wap|willcome|windows\ ce|windows\.ce|winwap|xda|zte) [NC]
RewriteRule .* – [E=W3TC_UA:_low]
RewriteCond %{HTTP_USER_AGENT} (acer\ s100|android|archos5|blackberry9500|blackberry9530|blackberry9550|blackberry\ 9800|cupcake|docomo\ ht\-03a|dream|htc\ hero|htc\ magic|htc_dream|htc_magic|incognito|ipad|iphone|ipod|kindle|lg\-gw620|liquid\ build|maemo|mot\-mb200|mot\-mb300|nexus\ one|opera\ mini|samsung\-s8000|series60.*webkit|series60/5\.0|sonyericssone10|sonyericssonu20|sonyericssonx10|t\-mobile\ mytouch\ 3g|t\-mobile\ opal|tattoo|webmate|webos) [NC]
RewriteRule .* – [E=W3TC_UA:_high]
RewriteCond %{HTTP_COOKIE} w3tc_referrer=.*(google\.com|yahoo\.com|bing\.com|ask\.com|msn\.com) [NC]
RewriteRule .* – [E=W3TC_REF:_search_engines]
RewriteCond %{HTTPS} =on
RewriteRule .* – [E=W3TC_SSL:_ssl]
RewriteCond %{SERVER_PORT} =443
RewriteRule .* – [E=W3TC_SSL:_ssl]
RewriteCond %{HTTP:Accept-Encoding} gzip
RewriteRule .* – [E=W3TC_ENC:.gzip]
RewriteCond %{REQUEST_METHOD} !=POST
RewriteCond %{QUERY_STRING} =””
RewriteCond %{REQUEST_URI} \/$ [OR]
RewriteCond %{REQUEST_URI} (sitemap\.xml(\.gz)?) [NC]
RewriteCond %{REQUEST_URI} !(\/wp-admin\/|\/xmlrpc.php|\/wp-(app|cron|login|register|mail)\.php|wp-.*\.php|index\.php) [NC,OR]
RewriteCond %{REQUEST_URI} (wp-comments-popup\.php|wp-links-opml\.php|wp-locations\.php) [NC]
RewriteCond %{HTTP_COOKIE} !(comment_author|wp-postpass|wordpress_\[a-f0-9\]\+|wordpress_logged_in) [NC]
RewriteCond %{HTTP_USER_AGENT} !(W3\ Total\ Cache/0\.9\.2\.3) [NC]
RewriteCond “%{DOCUMENT_ROOT}/wp-content/w3tc/pgcache/%{REQUEST_URI}/_index%{ENV:W3TC_UA}%{ENV:W3TC_REF}%{ENV:W3TC_SSL}.html%{ENV:W3TC_ENC}” -f
RewriteRule .* “/wp-content/w3tc/pgcache/%{REQUEST_URI}/_index%{ENV:W3TC_UA}%{ENV:W3TC_REF}%{ENV:W3TC_SSL}.html%{ENV:W3TC_ENC}” [L]
</IfModule>
# END W3TC Page Cache core
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ – [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

# BAD BOT EXCLUSION
# block known trouble makers dumb enough to
# announce who they are
SetEnvIfNoCase User-Agent “^Yandex” bad_bot

<Limit GET POST>
Order Allow,Deny
Allow from all
Deny from env=bad_bot
</Limit>

#Stop browser prefetching
SetEnvIfNoCase X-Forwarded-For .+ proxy=yes
SetEnvIfNoCase X-moz prefetch no_access=yes

# block pre-fetch requests with X-moz headers
RewriteCond %{ENV:no_access} yes
RewriteRule .* – [F,L]

RewriteCond %{HTTP_HOST} ^mywebsite$ [OR]
RewriteCond %{HTTP_HOST} ^mywebsitehost$
RewriteRule ^/?$ “http\:\/\/www\.mywebsite\.com” [R=301,L]