samsung LE40R73bd stand installation query?

Hi,

i have a samsung LE40R73bd.

I recently moved house, started putting the stand back onto my tv and the thing seems very wobbly.

Im not sure what i could be doing wrong

Its hard to explain so i have taken pictures of what i have.

http://img11.imageshack.us/img11/756/p1020801.jpg

The round plasic bit in the top left seats onto the underside of the tv nicely, with the plastic washer fitting onto that... i then put the actual stand next (again this fits perfectly) followed by the plastic thing in the top right and the metal thing in the bottom right... i then put in the 3 screws into a triangle formation (u can see which ones by the markings)

This all connects fine... but the thing seems very loose and wobbles alot something it didn't used to do before... Am i missing something? Any ideas?

Thanks
Sam