I am adapting Tony Stubblebine's example to do a simple update of a Lead record.
I can query the database, and insert new records.  When I attempt to update a
record that's there already, I get the message

  Expected a hash with key 'type' as first argument at soaptest6.pl line 49

from the statement
    $sfresult = $sforce->update(%lead);

I dumped out the hash: it has a key "type" which I inserted first, but it's a hash, right, the keys come back in random order, and PostalCode comes back first. 

I must be missing something simple.  Clue please.