I still doth think thats it,.. Like i say I was able to produce that error myself my simply trying to goto the the register wordpress address which i have renamed via rename wp-login.. it then shows me that same error.. and Usually whenever i see that error it is accompanied with the 404 error that they tried to visit the register page first.
also i don't know if shell commands are different but the path is not ./ its a hyphen -/