The miner is working for RiePool and XPoolX. However, there is a bug that produces many duplicate shares for powerful CPUs. This problem is present if many threads are used, but seems to disappear if mining with just 4 threads or less (and it seems possible to launch 4 instances using 4 threads for a 16 threads CPU without issue). I will investigate this.
AFAIR it can be something similar to that issue when you try to generate random numbers using loop having only one variable to store them you will get same numbers changing every second. Every CPU thread needs unique variable. I think to fix this you need to declare as many variables as possible at the very beginning of your code and then limit them to what you need.