On an Hudson 1.307 fresh install, when I enable Secrity, Hudson own users and
matrix based security, Hudson use j_acegi_security_check when I login and this
return a 404 error whith no possibilities to login.

When googling this problem, I am not the only one to have this problem and to
fix it, some people have defined a mod_rewrite redirect from
/hudsons/j_acegi_security_check to /hudson/j_security_check