Passed variable is not an array or object in mollom.class.inc on line 357

Hi,

I have mollom installed on a Drupal 6 set up. I'm trying to use it with the webform module, but the captcha seems to be never triggered and in the watchdog logs I get the following messages:

current() [<a href='function.current'>function.current</a>]: Passed variable is not an array or object in /usr/www/users/admin/sites/all/modules/mollom/includes/mollom.class.inc on line 357.

and

current() [<a href='function.current'>function.current</a>]: Passed variable is not an array or object in /usr/www/users/admin/sites/all/modules/mollom/includes/mollom.class.inc on line 421.

Followed by this:

200 GET site/03016e3b4b34d9028ad8bdb569e06b08 
Request: GET http://rest.mollom.com/v1/site/03016e3b4b34d9028ad8bdb569e06b08
Request headers:
  Accept = 'application/xml, application/json;q=0.8, */*;q=0.5'
  Authorization = 'OAuth oauth_consumer_key="03016e3b4b34d9028ad8bdb569e06b08",oauth_version="1.0",oauth_nonce="5ba46a661b37d848fafaec2683d738a2",oauth_timestamp="1321266815",oauth_signature_method="HMAC-SHA1",oauth_signature="JerPbsRGGudRCy82QYCoqY%2BqyZo%3D"'
Response:
array (
  'code' => '200',
  'site' => 
  array (
    'publicKey' => '03016e3b4b34d9028ad8bdb569e06b08',
    'privateKey' => '[my private key]',
    'url' => 'http://www.sanbi.org',
    'email' => '',
    'languages' => 'eng',
    'subscriptionType' => 'free',
    'platformName' => 'Drupal',
    'platformVersion' => '6.22',
    'clientName' => 'Mollom',
    'clientVersion' => '6.x-1.16',
    'servers' => '',
  ),
)

And then:

All servers unreachable or returning errors. The server list was emptied: http://rest.mollom.com/v1

I'd appreciate any help.