Plugin in the list but I can't use in the pipeline [ERROR]

Hello, I have installed a filter-plugin that I have created in a machine A, I have pack this plugin in a zip file to install it on a machine B that don't have access to Internet. When I install thix plugin with zip I don't have problem and the plugin appear in the list of plugin. But when I wan't to use this plugin in a pipeline I have this message :

"... error: Unable to load the requested plugin named elapsedStep of type filter. The plugin is not installed. ..." 

The plugin that appear when I ask to list plugin :


The pipeline of Logstash that used elapsedstep plugin :

elapsedStep {
        unique_id_field => "file"
        start_tag => ["jobStarted","Etape1","Etape2","Etape3","Etape4","Etape5","Etape6","Etape7","Etape8","Etape9","Etape10",
        end_tag => ["Etape1","Etape2","Etape3","Etape4","Etape5","Etape6","Etape7","Etape8","Etape9","Etape10",
        new_event_on_match => true

The beginning of the code of the plugin elapsedstep :

class LogStash::Filters::Elapsedstep < LogStash::Filters::Base

  PREFIX = "elapsed_"
  MATCH_TAG = PREFIX + "match"

  config_name "elapsedStep"

What can be the problem?