Question Problem installation bootmanager by Letama

Hello all !

I have some trouble to install the dualboot by Letama (http://forum.xda-developers.com/show....php?t=1880305, I didn't post on it, I don't have the right now).

I was on OpenSEMC 4.3.1.

My goal :
Have a dualboot with a kitkat OpenSEMC and a stock sony (I needed the ant+ connectivity).

With TWRP :
Flash of bootmanager 0.8.
Then for native loop : flash OpenSEMC kitkat.
But for the running the custom loop, I think I didn't understand well the different step for creating memory storage. Then I launch the installation of the sony stock, TWRP didn't succeed and tell me that :
- Can't succeed to mount folders like /system, /cache, etc.
- Can't succeed to install rom

It's not annoying at the moment 'cause the native loop launche OpenSEMC, but I try to understand how to install well the dualboot and the sony stock.

Thanks in advance for your help and answers !

(ps: sorry for my english )