following error message has been received when trying to install plug-in Email-ext plugin

hudson.util.IOException2: Failed to dynamically deploy this plugin
at hudson.model.UpdateCenter$InstallationJob._run(UpdateCenter.java:1176)
at hudson.model.UpdateCenter$DownloadJob.run(UpdateCenter.java:987)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: hudson.util.IOException2: Failed to install email-ext plugin
at hudson.PluginManager.dynamicLoad(PluginManager.java:394)
at hudson.model.UpdateCenter$InstallationJob._run(UpdateCenter.java:1172)
... 7 more
Caused by: java.io.IOException: Dependency maven-plugin (1.447) doesn't exist
at hudson.PluginWrapper.resolvePluginDependencies(PluginWrapper.java:467)
at hudson.PluginManager.dynamicLoad(PluginManager.java:384)
... 8 more

Need work around or solution, this is preventing a project from moving forward.