invalid memory alloc request size

Hi all,

I am running PostgreSQL 9.3.5 on Ubuntu Server 14.04 64 bit with 64 GB
of RAM.  When running pg_dump on a specific table, I get the following
error:

pg_dump: Dumping the contents of table "x_20131111" failed:
PQgetResult() failed.
pg_dump: Error message from server: ERROR:  invalid memory alloc request
size 18446744073709551613
pg_dump: The command was: COPY public.x_20131111 (...) TO stdout;
pg_dump: [parallel archiver] a worker process died unexpectedly

If I run a COPY TO file from psql I get the same error.

Is this an indication of corrupted data?  What steps should I take?

Thanks in advance,
Gabriel