Download version 7.0.0, with your normal browser, then add the module in your project
Excel Importer module is working in all version. This error depicts the missing one of the required module. You need to download MxModelReflection module from app store which is the dependency for this module.
Refer this learning path : https://gettingstarted.mendixcloud.com/link/module/142/lecture/1220/4.1-Importing-Data
I hope this helps you