Hey,
I just "hacked" the /html/lastRSS.php file, adding the line :
$rss_url = str_replace('&', '&', $rss_url);
between
// -------------------------------------------------------------------
// Parse RSS file and returns associative array.
// -------------------------------------------------------------------
function Get ($rss_url) {
and
// If CACHE ENABLED
if ($this->cache_dir != '') {
$cache_file = $this->cache_dir . '/rsscache_' . md5($rss_url);
$timedif = @(time() - filemtime($cache_file));
and it worked out fine for me.
Hope this helps

.