Access Denied in replying my own thread

Hello, yesterday I opened this thread: en.community.dell.com/.../21018288

Actually I'm not able in replying as it's displayed "Access Denied" when I push button "Reply". I can perfectly reply to other threads opened by other users... Surely it's my fault, but I can't understand what I've to do to solve this incredible situation... it seems it's locked...

Thanks and regards...