KeyNotFoundException: Morph3d

I am using Morph3d and is suddenly getting an error:

KeyNotFoundException: The given key was not present in the dictionary.
System.Collections.Generic.Dictionary`2[System.String,MORPH3D.FOUNDATIONS.MorphGroup].get_Item (System.String key) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Collections.Generic/Dictionary.cs:150)
MORPH3D.FOUNDATIONS.MorphGroupService.GetMorphGroups (System.String name)
MORPH3D.EDITORS.M3DCharacterManagerEditor.OnInspectorGUI () (at Assets/3dPartyAssets/MORPH3D/Scripts/Editor/M3DCharacterManagerEditor.cs:153)
UnityEditor.InspectorWindow.DrawEditor (UnityEditor.Editor[] editors, Int32 editorIndex, Boolean rebuildOptimizedGUIBlock, System.Boolean& showImportedObjectBarNext, UnityEngine.Rect& importedObjectBarRect) (at C:/buildslave/unity/build/Editor/Mono/Inspector/InspectorWindow.cs:1240)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

This error means that i am unable to add content to my morph3d characters.

Can anyone tell me what might be the problem? and how i can fix it?

Often Asset Store packages with Editor scripts will assume a certain folder hierarchy on import. Things like this will occur if you move these folders around.
So, most likely solution in your case:
Move the top-most Morph3d folder onto the top-most hierarchy in your project.