Can't access to back-office after changins admin's name folder

[Doruko]

First of all, sorry for bad english.

I've installed Prestashop 1.5.6.0 running on my own server (ubuntu server 12.04), and i've followed all the steps and all is fine until i change the admin's name folder, when i leave it as "admin", the server tells me that i've to change the name of the folder, but when i change it (For example, to admin1234), I can't access to the back-office (but i can enter the shop normally). Any though on what can be happening?

[vekia]

hello

by default, when you change name to admin - it should be changed automatically to other name by ps engine (from 1.5.5 version)

can you try to clear cache in your browser, then try to open admin page