Error while importing users: Field 'signature' doesn't have a default value

Log for Feeds

2012-08-26 18:58:05
2012-08-26 18:58:02
SQLSTATE[HY000]: General error: 1364 Field 'signature' doesn't have a default value
Original item

array (
'name' => 'Anuj',
'mail' => 'A@abc.com',
)
Entity

stdClass::__set_state(array(
'uid' => '251',
'roles' =>
array (
),
'status' => 1,
'feeds_item' =>
stdClass::__set_state(array(
'entity_id' => 0,
'entity_type' => 'user',
'id' => 'user',
'feed_nid' => 0,
'imported' => 1346007482,
'hash' => '97edcd213b66034a644b532ad518c365',
'url' => '',
'guid' => '',
)),
'name' => 'Anuj',
'mail' => 'A@abc.com',
'created' => '1346007485',
'is_new' => true,
'data' =>
array (
'contact' => 1,
),
))