warning: Invalid argument supplied for foreach()

The table was not created indeed. When I tried to email a page, I got an error that table forward_log does not exist. I created that table which took care of the problem.

I rewrote the function forward_schema() as shown below (definition of index is done as described in Drupal API documentation). Furthermore, I moved this function to forward.install. After uninstalling and installing the module in Administer > Site building, the table was created. I don't know which of the two actions helped. I started to explore the the Drupal module code only yesterday.

function forward_schema() {
$schema['forward_log'] = array(
'fields' => array(
'nid' => array(
'type' => 'int',
'unsigned' => TRUE,
'not null' => TRUE,
'default' => 0),
'type' => array(
'type' => 'varchar',
'not null' => TRUE,
'default' => 0,
'length' => 8),
'timestamp' => array(
'type' => 'int',
'not null' => TRUE,
'default' => 0)
),
'indexes' => array(
'nid_index' => array('nid'),
),
);
return $schema;
}