I figured out what the issue was.I was trying to reinstall Logbinder application without deleting previous traces in C:\ProgramData . (I wanted to configure input of Logbinder with different recipient.)
After I deleted all traces and reinstalled, I did not get any padding error and everything was fine and was able to collect logs too.
I have a doubt, even though I had set polling interval as 10 min, Logbinder takes too much time (more than 24 hours) for collecting admin audit events from MSExchange 2016. Website tells this delay occurs only for mailbox audit logs but I faced it for admin events as well. ( I am interested in admin audit events only)
Good thing is I am able to collect admin audit events.
Thank you for help.