BUG #11966: Cannot drop tables

The following bug has been logged on the website:

Bug reference: 11966
Logged by: Anandhi
Email address: anandhi(dot)arumugam(at)nexenta(dot)com
PostgreSQL version: Unsupported/Unknown
Operating system: Red Hat Linux 6
Description:

I need to drop a few tables in my Postgres DB. I tried the following

Cannot read termcap database;
using dumb terminal settings.
jiradb=> drop table "AO_3A3ECC_JIRACOMMENT_MAPPING";
DROP TABLE
jiradb=> drop table "AO_3A3ECC_REMOTE_IDCF";
DROP TABLE
jiradb=> drop table "AO_3A3ECC_JIRAPROJECT_MAPPING";
ERROR: cache lookup failed for constraint 1152954
jiradb=>

Why do i get this error? how do i fix this?