problem Namespace 'ICSharpCode.SharpZipLib.Core' not found, maybe you forget to add an assembly reference? (BCE0021)?

i’m use Vuforia but i’m so beginner, in my project when i run it show this two error:

Namespace ‘ICSharpCode.SharpZipLib.Core’ not found, maybe you forget to add an assembly reference? (BCE0021)

Namespace ‘ICSharpCode.SharpZipLib.Zip’ not found, maybe you forget to add an assembly reference? (BCE0021)

Workaround: take the assembly from the path below and put it to Assets/Plugins folder of your project.

C:\Program Files (x86)\Unity\Editor\Data\MonoBleedingEdge\lib\mono\2.0\ICSharpCode.SharpZipLib.dll