The most common errors are due to privileges.  Most of the content can be seen by anyone, but unless you have privileges to a game, you can't edit the game moves.  The exception to this is the pieces that have an adult rating.  To get adult privileges to the site, you need to fill out your birth date in your Control Panel and then send a PM to Chairman to let her know that this was done. Upon receiving the PM, she will grant you privileges.