In RouterOS v5.0beta5 the usermanager has problems with accessing the web-page. Here you can download the fixed packages:
http://www.mikrotik.com/download/share/user_manager_5_0beta5_mipsle.npk
http://www.mikrotik.com/download/share/user_manager_5_0beta5_ppc.npk
http://www.mikrotik.com/download/share/user_manager_5_0beta5_mipsbe.npk
http://www.mikrotik.com/download/share/user_manager_5_0beta5.npk
I have downloaded the ppc version for my RB1100 and now the login page is ok, but after login I got this error and the browser freezes:
Please contact your server administrator.
After that, the userman shows the same blank page as before it was fixed.
Same here, except that I only get an empty “Error:” message after login.
Still try… 
Tried today and couldn’t even get a page to display 
Have reverted back to 4.11 for time being.
Same here sir, i can access userman but can’t login, this error message “invalid/unknown respon from server”
i am not able login in http://router_ip_address/userman.
So many bugs in user manager beta5, ican’t create user againt. So just waiting the next version
I have the some problem om RB1000 .. when we have stable .. ?
Back to user manager beta4 againt sir.
User manager beta4 is working on routeros v5.0beta5 or should I need to downgrade the routeros as well to beta4?
You must downgrade ROS to beta4 first.
Same error on userman on v5.0beta6 too.
Can someone fix this pls.!
What’s new in 5.0beta6 (2010-Aug-10 13:22):
*) sstp - fixed memory leak;
*) wireless - changed band setting and added channel-width setting
*) wireless - support for 11n rates in 5&10mhz channels
*) wireless nv2 - fixed multiple problems including occasional tx stall;
*) made gps accessible through SNMP;
*) snmp - added GETBULK support, no more table caching - solves problems
with huge tables, routing tables currently are not available;
*) ssh - fixed public key authentication in case
when client is not verifying if server will accept the key;
*) fixed problem - MetaROUTER did not work on RB800, RB1000 & RB1100;
*) user manager is not working - will be fixed in next version;
*) intel 82576 (uncommon expensive chip) crash/reboot to be fixed in next release
Yup user manager it’ not working, Mikrotik staff already tell you in the cangelog.
It is fixed on RC1?
I am using the user maneger rb1100x2 v6.11 and is giving problem on the page administrator put 300 users and when I switch to page 2 to see the users gave problem, I am very concerned that this will always happen because I have to restart the rb1100x2 reopen the admin page again.
This is the error:
The Following client application error has occurred.
Can not Process Server Message (Phase 1)
Error Name: TypeErro
Error Message: Element is null libraries.
Please contact your server administrator
