Change the difficulty setting from auto to manual in the password field. Play with this setting to get between 5 - 15 shares per minute.

example here > https://bitcointalk.org/index.php?topic=1751272.msg25688111#msg25688111

-p c=BTC,d=0.1  or -p c=BTC,d=36

-i  << this sets the Intensity for the GPU(s) (see link above)

-t << this sets the number of threads for the CPU  eg -t 4 will use 4 cores (threads) of an 8 core CPU, this stops the PC from being slow when doing things on it, eg, mouse delays etc.
(Mining with your CPU)