Windows 7: PHILIPS Messenger Phone & Live Messenger issue.

Hi, I had this phone for a while now and have been talking to my relatives abroad for a while now. However, couple of days ago after I installed Windows 7 I started getting a weird error message. I hope someone can help me out here.

Her's what the problem is, whenever I try to call someone I get this message: "Not signed in to Windows Live Messenger" on the little screen of the PHILIPS phone, however I can see exactly who is online and offline, but I can't connect the call.

OS: Windows 7 Pro Upgrade.
Live Messenger: Version 2009 (Build 14.0.8089.726)
Fresh batteries charged to full.

Thank you.

PS. I am also on the Live Messenger Forum with this thread at the moment, but I am being told that it's most likely an issue with Windows 7, so here I am, hoping someone can help me with this.