Do not know how to upgrade Forge.

Good day.
I downloaded the latest version of Forge and I can't run it. The error message is:
spoiler=NullPointerException]
Thanks for your help.
I downloaded the latest version of Forge and I can't run it. The error message is:
spoiler=NullPointerException]
- Code: Select all
Forge Version: 1.5.20-SNAPSHOT-r26249 (mixed revisions detected; please update from the root directory)
Operating System: Windows 7 6.1 x86
Java Version: 1.7.0_55 Oracle Corporation
java.lang.NullPointerException
at forge.quest.QuestController.getDraftDecks(QuestController.java:158)
at forge.screens.home.quest.CSubmenuQuestDraft.initialize(CSubmenuQuestDraft.java:96)
at forge.view.FView.initialize(FView.java:121)
at forge.control.FControl$3.run(FControl.java:243)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$200(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Thanks for your help.