1. We have added a fix in lib/lib.filterinput.php
changed :
if ( ! preg_match('#^[&a-zA-Z0-9\.:_/-\s]+$#uD', $str)) {
to
if ( ! preg_match('#^[&a-zA-Z0-9\.:_/\-\s]+$#uD', $str)) {

2. We have added a fix in .htaccess for chat window to work.
<FilesMatch "(index\.php|check\.php|write\.php|text\.php|users\.php|ajax\.adm_server\.php|ajax\.server\.php|paypal\.php|tasks\.php|tiny_mce_gzip\.php|index_tiny\.php|scormXmlTree\.php|soaplms\.php|scorm_page_body\.php)$">