S7 300 Software Redundancy Problem

I am working on a S7-300 system but face some problems.
My configuration is two sets of S7-300 315-2DP and two sets of ET200M.
When I include the SWR in OB1, I have the following error:

"STOP caused by STOP command
Breakpoint in user program. Startup OB(OB100)
Priority class: 27
FC number: 100
Module address: 2720
Previous operating mode: STARTUP (warm restart)
Requested operating mode: STOP (internal)
Internal error, Incoming event."

I think I may have mistake in OB100 setting but just can't figure out.
Could anyone help to identify the problem or provide a workable sample program?
Thanks ahead.

Hey Borient,

I am also working on S7 300 redundant project.

Can you send snap shot of OB100 which helps me to find what is the exact problem.