Why wont my iPhone 4 sync certain playlists? iOS 5.1.1 and iTunes 10.6.3

Question

Hello!
Recently, my iPhone 4 wont sync any new playlists. When I tick the box for the playlist I want to sync, the data boxes move and the song count increases, but when I click sync, it does nothing and the playlist isn't visible on the iPhone.
So far, I've completely wiped the iPhone (doing a full restore) and tried to sync from scratch, but it seems only to be syncing the ones I had on already before I wiped it, which is very odd. Any ideas anyone?

Answer 1

Well, you have to minimally upgrade to Snow Leopard 10.6.8:
Upgrading to Snow Leopard
You can purchase Snow Leopard through the Apple Store: Mac OS X 10.6 Snow Leopard - Apple Store (U.S.). The price is $19.99 plus tax. You will be sent physical media by mail after placing your order.
After you install Snow Leopard you will have to download and install the Mac OS X 10.6.8 Update Combo v1.1 to update Snow Leopard to 10.6.8 and give you access to the App Store. Access to the App Store enables you to download Mountain Lion if your computer meets the requirements.
     Snow Leopard General Requirements
       1. Mac computer with an Intel processor
       2. 1GB of memory
       3. 5GB of available disk space
       4. DVD drive for installation
       5. Some features require a compatible Internet service provider;
           fees may apply.
       6. Some features require Apple’s iCloud services; fees and
           terms apply.
But this costs money, so you can't do it. That means your are stuck where you are.