Hello,
I have been working with c-cex-yuriy on IRC to try and fix the issue with their wallet.dat. After reading the debug and error messages, we came to the conclusion that the wallet.dat has a corrupted or missing section, possibly due to the daemon being terminated before letting it flush data to disk. After attempting numerous repair tools on the damaged wallet.dat, I offered to compare C-Cex's broken wallet.dat to a working wallet.dat (empty one generated on my own computer) in a hex editor and attempt a manual repair of the wallet.dat. Please understand there is no guarantee that I will be successful in fixing the wallet in this way, and it is strictly best-effort. Yuriy accepted the offer, and will be sending me the wallet.dat over a secure tunnel. At the conclusion, regardless of outcome, I will shred all copies on my hard drive of C-Cex's wallet.dat using the 'shred' command. I will also be in contact with the developer of VNL over bitmessage, john-connor.
Thank you,
tf2honeybadger / Kevin
Poloniex Wallet Manager