RL-Flash + RTX Can not wok together?

Hi
I have MDK-Professional 4.21.
I can not start working with RTX + Flash FIle System
When I add library fs_CM3.lib to project I can not enter to Main.
It stop in

 LDR     R0, = __main
               BLX     R0

On instruction BKPT I do not know how to make it run.
When I remove this library from system I can get to main an RTX works fine.
thx