From an announcement by the MLJ Trust this morning:
This is probably the biggest announcement the MLJ Trust will ever make. Starting from tomorrow, April 12th, all 1,600 recorded sermons by Dr. Martyn Lloyd-Jones will be available to download, at no cost, to anyone who wants to listen to them! There are no exceptions, so the Ephesians sermons, Romans sermons, etc. will all be available (it will take a few days to make sure that they are all included in the library). All one has to do is join the MLJ Library (membership is free of course) and start to download! Simply go to our newly updated site at http://www.mljtrust.org and click on “MLJ Library”.…
This announcement eMail has been timed to coincide with our formal announcement at “Together for the Gospel”. This morning (Wednesday, April 11th), we will be making the announcement on stage to the approximately 7,000+ Christian leaders and teachers who will be attending, and we never forget that the participation of the MLJ Trust at this conference was made possible by the kind support of our subscribers.
[Aside: I just tried the link for MLJ Library and it didn’t work — my guess is that the server is overloaded with requests. Check back later if it doesn’t work now.]

I joined the membership of the MLJ archived sermons yesterday and I continue to get an error when I try to access it.
I couldn’t get in when I just tried, either, though I have had access many times. My guess is that they are having a server problem. As my tech-friend often says, “Just wait an hour or two and try again…” :)
And you might just double check your user name and password — they are case sensitive. I tried another user name and password and was able to login just fine. And if all else fails, just create a new user name.