First thing try is adjusting the number of repeats on the volume up and down commands. In ccp select one of the commands. Bring up the macro screen. Then double click on the command. Then adjust the number of repeats from three to one or two. This should fix it.

If that doesn't work try using another IR code set from the universal database.

If that doesn't work it could be rf base station related (if you are using rf). You might need to adjust the output level of the emitter that is connected to the surround receiver. And also make sure the ir ports are assigned in the programming software i.e. not set to all.

And the only other thing you could try is importing the hex commands or manually learning the commands.