The validate blocks in datamanager files that we saved in 2.7 are not executed automatically in 2.8. Scheduled chain actions are executed without loading the validate blocks. This is a cause of a lot of work for us. We need to open the datamanager file and execute the validate block.
This looks like another legacy issue, please bare with us while we fix this (it may take a few days). In the meantime you can execute the block in 2.8 and save the file to permanently fix this problem.
This error occurred because we changed the validate data block to require you to click the "Execute" button. In 2.7 the validate data block did not require an execute button, instead it executed automatically whenever you make any changes. When you open the file in 2.8 because you've never clicked on the execute button the block becomes invalid.
We've put a fix for this issue in tonight's Omniscope 2.8 release (b1099). Please let us know if this resolves your problem.
As mentioned above you can simply load the file in 2.8, click the "Execute" button and save the file to fix this problem immediately.