"jquery_file_upload.id is part of the primary key but is not specified to be 'not null'"
The error message is about the schema currently used by the module, which defines the primary key using the following code.

function jquery_file_upload_schema() {
  $schema['jquery_file_upload'] = array(
      'description' =&gt; t('Stores files sizes for each user.'),
      'fields' =&gt; array(
          'id' =&gt; array(
              'description' =&gt; t('auto increment'),
              'type' =&gt; 'serial',
              'size' =&gt; 'normal',
          ),
          'uid' =&gt; array(
              'description' =&gt; t('registered user'),
              'type' =&gt; 'int',
              'unsigned' =&gt; TRUE,
              'not null' =&gt; TRUE,
              'default' =&gt; 0,
          ),
          'file_name' =&gt; array(
              'description' =&gt; t('File Name.'),
              'type' =&gt; 'varchar',
              'length' =&gt; '255',
              'not null' =&gt; TRUE,
          ),
          'file_size' =&gt; array(
              'description' =&gt; t('File Size.'),
              'type' =&gt; 'float',
              'size' =&gt; 'big',
              'default' =&gt; 0,
          ),
      ),
      'primary key' =&gt; array('id'),
  );
  return $schema;
}


The correct definition would be the following one, as the fields that are part of the primary key should be declarated as "NOT NULL."

function jquery_file_upload_schema() {
  $schema['jquery_file_upload'] = array(
      'description' =&gt; t('Stores files sizes for each user.'),
      'fields' =&gt; array(
          'id' =&gt; array(
              'description' =&gt; t('auto increment'),
              'type' =&gt; 'serial',
              'size' =&gt; 'normal',
              'not null' =&gt; TRUE,
          ),
          'uid' =&gt; array(
              'description' =&gt; t('registered user'),
              'type' =&gt; 'int',
              'unsigned' =&gt; TRUE,
              'not null' =&gt; TRUE,
              'default' =&gt; 0,
          ),
          'file_name' =&gt; array(
              'description' =&gt; t('File Name.'),
              'type' =&gt; 'varchar',
              'length' =&gt; '255',
              'not null' =&gt; TRUE,
          ),
          'file_size' =&gt; array(
              'description' =&gt; t('File Size.'),
              'type' =&gt; 'float',
              'size' =&gt; 'big',
              'default' =&gt; 0,
          ),
      ),
      'primary key' =&gt; array('id'),
  );
  return $schema;
}


There is nothing you can do, if not opening an issue report for the module, in its issue queue. Be sure there isn't already a report about that.