Can you update to a newer version of bitconid?
15.2 or something in the 17 branch?
The version you are running is vulnerable to CVE 2018-17144 https://nvd.nist.gov/vuln/detail/CVE-2018-17144

Either way it looks like something in the DB is corrupted.

Backup your wallet file (you are doing that anyway right???), remove the blockchain data and re-download.

-Dave