Using drupal 7.27
Colors module working with FullCalendar

I created a content type for a user to add a calendar event, each user has a color. When the user adds content-->Add Calendar Event, the error message shows at the top:
Notice:
Undefined property: stdClass::$uid in user_colors_classes() (line 56 of /blablabla/sites/all/modules/colors/includes/user.colors.inc).

When the page is refreshed, the error goes away.

I can create calendar events without issue after I refresh the page. Seems like the module works fine, the error may not be valid.

Line 56 is the last line:

if (variable_get('colors_users_enabled', FALSE)) {
    if ($entity->entity_type == 'user' || $entity->entity_type == 'node') {
      $class_names[] = 'colors-users-' . $entity->uid;

What is the best way to get rid of the error message?