Error building Player: CommandInvokationFailure: Unable to convert classes into dex format. See the Console for details.
C:\Program Files (x86)\Java\jre7\bin\java.exe -Xmx1024M -Dcom.android.sdkmanager.toolsdir=“B:/adt-bundle-windows-x86_64-20131030/adt-bundle-windows-x86_64-20131030/sdk ools” -Dfile.encoding=UTF8 -jar “C:/Program Files (x86)/Unity/Editor/Data/BuildTargetTools/AndroidPlayer\sdktools.jar” -
Some possible solutions on THIS forum post. You’ll have to skim it some, but there are several fixes that people with similar errors got working.