Londiste replication fails intermittenly
Sorry for the answer, but I cannot comment....

You got the pretty straightforward message :

ERR: mydb_data_0: [ev_id=84594950,ev_txid=702851528] duplicate key value violates unique constraint "dmn_pkey"


It says you're trying to insert a value which is already present in the table.
You have to work on your enqueue/dequeue process to avoid duplicates.