is there anything in the rscd.log on the file server?
during the blappconf wizard the connection that creates the directory will come across as 'System:System' so you need either:
The Exports file was incorrect on the FileServer side, just odd it only affected DASD.
I ran into this same issue. For me, just changing the exports file to * rw,user=root did not fix it. I also needed to comment the nouser line in the users file. If I did this, the app server started up and I didn't need the System:System entry in users.local.
Why do the ACLs need to be bypassed for the app server to start? If bladmin is in users.local, shouldn't this be enough?