I have undeployed the 1.1.0 solution and when attempting to deploy the 1.2.0 solution I am getting the following Powershell error. Enable-SPFeature : The Feature is not a Farm Level Feature and is not found in a Site level defined by the URL.
So I tried to upload the wsp solution file to the Soluion Gallery but then could not activate it. I received the following error message
This solution contains invalid markup or elements that cannot be deployed as part of a sandboxed solution. Solution manifest for solution '956715d5-f34c-4b00-bfb7-8c35d5fa0f62' failed validation, file manifest.xml, line 3, character 4: The element 'Solution' in namespace 'http://schemas.microsoft.com/sharepoint/' has invalid child element 'ApplicationResourceFiles' in namespace 'http://schemas.microsoft.com/sharepoint/'. List of possible elements expected: 'FeatureManifests, Assemblies, ActivationDependencies' in namespace 'http://schemas.microsoft.com/sharepoint/'.