pmdg 744 decent profile

[mrinfo]

Hey there simmer's!
I'm having a bit of a problem with my PMDG 744, need help a.s.a.p.
Each time i program a new altitude into the FMC enroute, priming it to descend to the next FLT level..(Not pushing the button)..Noting happens when A/C arrives at the next way-point.
The Queen is designed to descend automatically, when A/C enters the decent profile. I've seen it done by other Simmer's however, i can't seem to make it happen.
What I'm i doing wrong?

[BlackAce]

Make sire that your ALT in the MCP is to the level that is told to you by ATC or whatever. Aslong as you're using LNAV VNAV it should be fully automated.