Some machines not showing as compliant

HI,

I wonder would someone be able to shed some light on an issue i am having with some machines not reporting back as having software installed. Yet when i go onto the machines and check the agent it shows as having run successfully.

I f i run a compliance report it shows these machines as having "not applied" but they have, they just aren't reporting back.

Hopefully someone has experienced this before. I am using Altiris 7.1

Thanks