in reply to DBI 1.3.7->1.4.5

I'm not too sure about what version it changed in, but in newer versions the number of params to selectall_hashref has changed:

$ary_ref = $dbh->selectall_hashref($statement);

$hash_ref = $dbh->selectall_hashref($statement, $key_field);

To quote the man page:
This utility method combines the prepare, execute, and fetchall_hashref entries elsewhere in this document into a single call. It returns a reference to a hash containing one entry for each row. The key for each row entry is specified by $key_field. The value is a reference to a hash returned by "fetchrow_hashref".