I have Metatrader 4 and for some reason experts don't work for me...

I put the .mq4 file in the /experts folder then compile it and it's possible for me to attach it to the chart. So i attach it to the chart and just select "allow live trading". But it never trades?!

at the moment i have Scalp net, Renko trader v.5 and 100pips v_3 auto expert traders running and they have been running for about 3 days and not traded once, does anyone have an idea why?!