Error building Player: Win32Exception

Error building Player: Win32Exception: ApplicationName=‘javac.exe’, CommandLine=‘-bootclasspath “C:/Program Files/Android/android-sdk-windows/platforms/android-21\android.jar” -d “C:\Users\Nicolas\Documents\New Unity Project 2\Temp\StagingArea\bin\classes” -source 1.6 -target 1.6 -encoding UTF-8 “com\IceCraftedGames\OstrichRun\R.java” “com\unity3d\ads\android\R.java”’, CurrentDirectory=‘C:\Users\Nicolas\Documents\New Unity Project 2\Temp\StagingArea\gen’

Im having this Error and i need help! Please write exactly what i need to do!

Tell me how