I import step by step.
After step 4, I go to ~/App_Data/CMSTemp/ImportExport/Files - Include In Project - rebuilt

then have error:
Error 2 The name 'cmsrepeaterImageSlider' does not exist in the current context D:\HOC TAP\UngDungTinHoc\Kentico\TestLocal\Sources\App_Data\CMSTemp\ImportExport\Files\CMSWebParts\MediaLibrary\ImageSliderBasic.ascx.cs 157 9 CMSApp
Error 3 The name 'ltlScript' does not exist in the current context D:\HOC TAP\UngDungTinHoc\Kentico\TestLocal\Sources\App_Data\CMSTemp\ImportExport\Files\CMSWebParts\MediaLibrary\ImageSliderBasic.ascx.cs 161 13 CMSApp