postgis - How do I use st_dwithin with meters?

I am trying to follow PostGIS ST_Buffer Radius Help to use a 50 meter distance but postgis is returning an error.

I am trying the following SQL,

SELECT id FROM table 
WHERE ST_DWithin(ST_GeogFromText('SRID=4326;POINT(-3.165356 55.926665)'), 
      geography(geometry), 50);

The hints indicated at ST_GeogFromText are,

• function st_geogfromtext(unknown) does not exist at character 92


• No function matches the given name and argument types. You might need to add explicit type casts.

Any help/alternatives would be appreciated.