Importing a web part from 2010 to 2013 SP

I followed this guide (http://www.c-sharpcorner.com/blogs/exporting-and-importing-web-parts-in-sharepoint-2013) on importing web parts but I got an error with opening the file once I uploaded the web part. Is there something different involved when importing a web part from a 2010 site to a 2013 site? Or is it because the file the web part is pulling from is on the old website? Permissions problem? 

 

I'm very new to SharePoint (<1-month experience) but I think I'm on the right track. Thanks for any help.