Hi Ramji.
I tried this already to check if this would help you. But didn't make any difference in create/change.
Please restore Not specified for Field attributes per Activity because that's how the setup is in standard. It's "Not specified" in my system and i am able to change/create BP and enter value for the attributes.
There is something else which we haven't identified yet. Did you raise an OSS already for this?
Regards
Dhilipan