Hi,
I am sorry for the delay, I was very busy with Server maintenance the last few days. This ADO bug is very strange here. For one try during my testing with your subscription email, I got the error message.
But after that, it went fine all the time. No more error. So I am still not able to reproduce it

.
Can you try to set the Maintenance->Log Level to Debug and let NewsMerge run until the next error. It will possible output some more informations.