Break Iphone 3.1.3 again with new tool Spirit - One Click tool,

http://www.iclarified.com/entry/index.php?enid=9201

After jail break, do the following to enable you sync any "P" applications.

How to Patch the Mobile Installation file in OS 3.0 for iPod Touch/iPhone

Go to CydiaTap on Manage tabTap on sourcesTap on “Edit” and then on “Add” , type in the hackulo.us repository which is http://cydia.hackulo.us
Tap on Add SourceAfter the source is added, go to “Search” in Cydia and search for AppSync for OS 3.0
Install and ConfirmSelect the applications you want and click sync, they will be synced without any errors