Finally fixed the problem with entries not being associated with bjcp
results. It was a database issue: the sequence,
contest_bjcpjudgingresult_id_seq wasn't owned by
contest_bjcpjudgingresult's id column. To fix it, the following SQL
statement needed to be executed:

ALTER SEQUENCE contest_bjcpjudgingresult_id_seq OWNED BY
contest_bjcpjudgingresult.id;