Uninstall the beta version.Possible cause for this is issue is that an earlier version of Messenger Plus is installed that is causing an incompatibility with Windows Live Messenger.
If neither of these solves the problem, please post back.The following steps would guide you to configure security settings, verify if software is the latest, and remove third party software.
First, try to disable your firewall completely, test the messenger software’s functionality regarding your issue.
After which configure your firewall and test again the software’s functionality regarding your issue;
1. To configure Windows Live Messenger through the most common firewalls, visit http://spaces.msn.com/messenger-support and look for steps under "How to enable Windows Live Messenger through a Firewall" on how to enable Windows Live Messenger through the most common firewalls. Click the appropriate link based on the firewall you have installed on your computer.