There is a problem with your environment because the Application Express files have not been loaded.
Video Tutorial
Issue: There is a problem with your environment because the Application Express files have not been loaded. Please verify that you have copied the images directory to your application server as instructed in the Installation Guide. In addition, please verify that your image prefix path is correct. Your current path is /i/ (it should contain both starting and ending forward slashes, such as the default /i/). Use the SQL script reset_image_prefix.sql if you need to change it.
Solution
1) Create folder “i”
1) Go to webapps folder
Location: $CATALINA_HOME/webapps
2) Create new folder and rename it to “i”
3) Go to APEX folder (Installation folder)
4) Go to IMAGES folder (Installation folder)
5) Copy all files from Images folder
6) Go to the “i” folder and paste all files here
Manage List Application in Apache Tomcat
1) Open browser and open tomcat webserver i.e localhost:8080/manager
2) Click on List Application
3) Find /i path in list application (see below image)
4) Start or reload it
5) Open APEX url in browser and press CTRL+F5