Jean, it may not be getting enough light. Dendrochilums are fairly high light species. I grow mine in bark mix, clay pot for most with my Oncs and Phrags. This one will end up in a clay pot, once I go to pot it up. Which species do you have?
I bought the plant in 1996! with 3 flower stalks and about 150 tiny flowers, labelled 'Dendrochilum ??'. The plant had 2 new shoot in 97, then went through a very painful time, dying almost completely back. It is recovering since 2002, had 3 new shoots last year, and gets a lot of sun; so I am still confident it will be reflowering one time! Jean