diff --git a/lib/redmine/plugin.rb b/lib/redmine/plugin.rb
index 11255e02d3a..0adc641e471 100644
--- a/lib/redmine/plugin.rb
+++ b/lib/redmine/plugin.rb
@@ -63,6 +63,15 @@ def def_field(*names)
     
     # Plugin constructor
     def self.register(id, &block)
+      # check if the plugin is in the correct location
+      unless Engines.plugins.collect(&:name).include? id
+        if Redmine::VERSION::MAJOR <= 1 && Redmine::VERSION::MINOR < 1
+          ActiveSupport::Deprecation.warn "WARNING: The #{id} plugin needs to be inside #{File.join(RAILS_ROOT, 'vendor', 'plugins', id.to_s)}"
+        else
+          raise "ERROR: The #{id} plugin needs to be inside #{File.join(RAILS_ROOT, 'vendor', 'plugins', id.to_s)}"
+        end
+      end
+      
       p = new(id)
       p.instance_eval(&block)
       # Set a default name if it was not provided during registration