why can't I upgrade the new OS 5 ON MY BLACKBERRY 8900 CURVE?

[choco123]

when i go on options > wireless update
it says there are no updates available
even on my desktop software it says I am currently on OS 4 but there are no updates available.
when I downloaded the OS 5 onto my desktop it still says there are no updates.
please can someone help, I'm really frustrated.

 

[FrancisG]

There are 4 things you need in addition to downloading the OS5
Hope it helps
http://us.blackberry.com/apps-software/devices/