Have you tried step two of the wiki?
2. Re-prioritize your network adapter order:
For XP/2000: Start > Control Panel > Network Connections, then, on the menu bar, click Advanced > Advanced Settings and put Hamachi at the top of the list.
For Vista: Start > Control Panel > Network and Sharing Center, then, on the left side panel, click on 'Manage Network Connections'. Now press Alt, click on Advanced > Advanced Settings and put Hamachi at the top of the list.
For Windows 7: Start > Control Panel > Network and Sharing Center, then, on the left side panel, click on 'Change adapter settings'. Now press Alt, click on Advanced > Advanced Settings and put Hamachi at the top of the list.
The above is usually the cause of a lot problems. Also what version of hamachi are you using?