Did you check in the Experts log?
Do you have both buy and sell enabled in the EA common tab?
Invalid trade volume.
When you make a trade with too high / low /invalid lot size that the platform can not accept than it has a problem closing the trade.
I will fix this error soon.
Please wait for the software update,
If after the update you are facing the same problem then please try to work with a different platform than the one you work with now.
Do not work with a live account Before you test the EA on a demo account,
Error 4109 can occur for several reasons: you did not enable automatic trading,
Or your broker does not allow automatic trading, anyway wait for software update.