Peggy... it appears that this is nothing truly 'exotic' about this filter. You MAY be able to go to a Hobby Shop or Craft Shop and find some 'fine mesh foam' and cut to fit and still have some to spare!
light is in red means standby mode.
Flashes in red - The projector is in abnormal status. Symptoms are indicated by
number of flashes. Address the problem in accordance with the
following. If a symptom persists, despite having taken measures below, consult with qualified Sony personnel.