Scheduled transactions not posting automatically

I have set up some scheduled transaction and in the general preferences dialog box ticked the 'post pending scheduled transactions' under program start.

I expected the scheduled transactions to automatically be posted to the relevant accounts the the dates that they are due to go out of my account, but this is not happening. The only way I can get them to show up in my accounts is if I post them manually, which I do not want to have to do each month.

I noticed that Christopher had the same problem back in February 2015, but no one answered his query and although he managed to resolve it himself he did not say how.

Please could someone help me, I have only just started using Homebank so it is all very new to me and I have not been able to find the solution anywhere else.