Hi Mary,
Just check if the class file "Display.class" is present in the directory WEBLOGIC_HOME/myserver/servletclasses/weblogic/taglib/counter.
If you do not have the above mentioned directory, then create one, and place the class file inside it.
Here is how to create the Display.class class file.
1. Compile the Display.java present in WEBLOGIC_HOME/examples/jsp/tagext/counter
2. Place it in the WEBLOGIC_HOME/myserver/servletclasses/weblogic/taglib/counter directory
Once this is done, your custom tag will work.
Regards,
Prasad