Hmm ... which sequence is entry.id actually referring to on the source database? I suspect that it is linked to some differently-named sequence like "entry_id_seq1" and the source's "entry_id_seq" is not in truth doing anything (and, in particular, hasn't ever been advanced, so when the restore script sets its value to 1 it's clobbering the other sequence).
That was it, exactly. Thanks. I dropped the unused entry_id_seq, and renamed the existing sequence using an ALTER TABLE .. RENAME TO statement.
The methodology that pre-8.2 pg_dump uses for serial columns is vulnerable to quite a number of problems if serial sequences don't have the expected names, and this seems to be another one.
I assume it would not be advisable to use the 8.2 version of pg_dump, if I intend to restore to an 8.1 database, correct?