SMS capabilities / issues

I have manually added mobile numbers for several contacts. When they are
offline, some show with a cellphone icon, and others do not. If I double
click on those with a cellphone icon, I am offered to send a text message,
but on the others, it says I would be sending an offline message. Why can't
they all receive SMS text messages if I have entered a mobile number?

Also, and possibly related, I don't have all of the icons across the top of
the LIve Messenger screen, just the first two, open your email box, and view
your sharing folders. Why is this, and is that possibly related to the SMS
issue. I have uninstalled and reinstalled with no joy.

Thanks,

Don L.