Comment ajoute extension file pr faire upload

Bonjour,
j.ai des problem pour faire les upload voici mon code

if( $CONF->getval("extmode")!="gif","jpg","jpeg","png","txt","nfo","doc","rtf","htm","dmg","zip","rar","gz","exe" )
{
$fileext = strtolower( substr( strrchr( $_FILES[$fname]['name'], "gif","jpg","jpeg","png","txt","nfo","doc","rtf","htm","dmg","zip","rar","gz","exe" ), 1 ) );
$extarray = explode( "gif","jpg","jpeg","png","txt","nfo","doc","rtf","htm","dmg","zip","rar","gz","exe", $CONF->getval("extensions") );

if( $CONF->getval("extmode")=="except" && in_array($fileext,$extarray) )
{
$errors[$field['id']] = $_LANG['ext_not_accepted'] . " (.$fileext)";
continue;
}
elseif( $CONF->getval("extmode")=="only" && !in_array($fileext,$extarray) )
{
$errors[$field['id']] = $_LANG['ext_not_accepted'] . " (.$fileext)";
continue;
}
}

// block .htaccess files
if( $_FILES[$fname]['name']==".htaccess" )
{
$errors[$field['id']] = $_LANG['ext_not_accepted'];
continue;
}

a chaque fois il me dise "Extension not accepted"

Configuration: Windows XP
Firefox 2.0.0.12