When you get an error like this it means that there is an include on your page and the included file cannot be found in the location specified. Based on the error message it looks like you have an include in your index.php page. The include starts with a ../ in the path. It looks like the page you are working with was in a subfolder in your test site. You will need to either replicate the exact same file and folder structure as you have for the testing server, or you will need to adjust the paths for the includes.
I would suggest that you get the files organized just like on your local testing server to avoid issues like this. When you were creating the page and applying eCart to them the include lines and other code was added to the page based on where that page was in relation to the root of the site. Since the page was in a sub directory the include paths for the eCart files were written with a ../ in them so it would go above the current directory and then look for the eCart folder.