The forum at http://www.4xlab.net/cs/forums/16/ShowForum.aspx is open to all registered users and provides more than enough source code to start doing practical experiments with Forex mechanical trading systems.
The forum at http://www.4xlab.net/cs/forums/6/ShowForum.aspx is an invitation only forum. You gain access by contributing to the forums here. May I suggest taking a look at the FX University, where we will start learning about trading the Forex market using mechanical trading systems. Participation in the university courses will lead to admission to the inner source code forum.