mask/opacity map problem

http://ods-visuals.mysite.wanadoo-members.co.uk/page1.html

not sure if its a bug or not,the white you can see is the background colour so the mask map is working but its also hiding the geometry behind the plant.any ideas guys?im probably doing something wrong!
one thing that is strange,it didnt happen while using vray free.

cheers jow

Set the secondary rays bias in the Global switches rollout to a small positive value (like 0.001) and it will go away.

This happens because you have overlapping faces on the plants.

Best regards,
Vlado

cheers vlado ill try that and get back you.

that solved the problem thanks.

Another issue that looks very similar to that..

If using an opacity map in a vray material, if you check the affect alpha, it appears very much like that.