show my message error

RouterOS The User Manager
1

hi there
i can’t show my custom mesage in login page.
i change errors.txt , but still i recive error like E=900 R=0,
how change it into my custom message

even i try to this code

<div style="color: #c1c1c1; font-size: 9px">Powered by MikroTik RouterOS &copy; 2005-2008</div>
$(if error=="E=900")<br /><div style="color: #FF8080; font-size: 9px">  MY CUSTOM MESSAGE    </div>$(endif)

but didn’t work.
can u help me!