New users's activation - preview failed

Hi there,

I have a very strange and very inconvenient "problem" for 2 days now:

On our forum www.bones-tff.org new accounts will be activated by an admin.
Usually, when somebody applied to be a member, I got 2 emails, one with an activation link and one with a link where I could check details of that new potential member's account, like email and so on.
Now when I get those emails, I still can activate a new member with one of the links, but another one, where I usually would check for the details, leads me to NOTHING but a message "Sorry, but this user does not exist." No access to account. What is wrong? I know that this new user doesn not "exist" because he/she wasn't activated yet, but previously this link always gave me an access to his profile details...

I created a new member just to test it:
Member's name: probe_account
As usual, I got 2 emails:
1st: "New user registration"
A new member, called "probe_account", has joined The Founding Fathers. You can view his or her profile using the following link:
http://www.bones-tff.org/profile.forum?mode=viewprofile&status=unregistered&u=probe_account

and 2nd: "New user account"
The account owned by "probe_account" has been deactivated or newly created, you should check the details of this user (if required) and activate it using the following link:
http://www.bones-tff.org/act?u=1&ak=4125e1ef2d79b632

The 2nd link with the activation works as usual but the 1st one only leads me to a message: "Sorry, but this user does not exist." Though normally it would give me an access to the profile....
(I surely still can see all those details using "inactive users", but it was very fast and convenient with the email link...)

And ideas how I can get back this particular feature?
Or was it a bug before and now it's working how it should have been always??