Marco,
I found out, that in my mdi-application i had an "abort" in a OnCloseQuery event. Due this, the datamodule forms didn't close the datasets and the datamodules aren't freed. So doa tries to close all the dataset and throws the AV's. After removing the abort-command it's better, but still sometime AV are raised in the DOA - lib.
It could be that there is a bug in my software, which was supressed in doa 3.4
Greetings
Sven