How to resolve java errors that pop up when loading Mirth Connect Administrator

I recently inherited a server running Mirth Connect with little documentation. The Mirth Connect server itself is running fine on the server, and I am able to connect to the web portal via port 8443 (and can log into the web-based administrator without any issues).

My problems occur when I run the ice tea java web start. Things go fine up until I enter my credentials and the interface starts to build; I receive the following error notice:

Could not load code template plugin: com.mirth.connect.connectors.http.HttpSenderCodeTe mplatePlugin
net.sourceforge.jnlp.runtime.JNLPClassLoader.loadClass(JNLPClassLoader.java:1535)
java.lang.Class.forName0(Native Method)
java.lang.Class.forName(Class.java:191)
 com.mirth.connect.client.ui.LoadedExtensions.initialize(LoadedExtensions.java:131)
com.mirth.connect.client.ui.Frame.initializeExtens ions(Frame.java:484)
com.mirth.connect.client.ui.Frame.setupFrame(Frame .java:382)
com.mirth.connect.client.ui.Mirth.<init>(Mirth.jav a:62)
com.mirth.connect.client.ui.LoginPanel$8.doInBackg     round(LoginPanel.java:438)
com.mirth.connect.client.ui.LoginPanel$8.doInBackg round(LoginPanel.java:407)
javax.swing.SwingWorker$1.call(SwingWorker.java:29 6)
java.util.concurrent.FutureTask.run(FutureTask.jav a:262)
javax.swing.SwingWorker.run(SwingWorker.java:335)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
java.util.concurrent.ThreadPoolExecutor$Worker.run  (ThreadPoolExecutor.java:615)
java.lang.Thread.run(Thread.java:745)

It pops up when the login dialog reads: "Please wait, loading extensions" and it continuously pops up until the dialog reads: "Please wait, loading channel editor" at which point the dialog box seems stuck on that loading screen.

I am using Mirth Connect 3.1.1, running it on Ubuntu 14.04 on an AWS EC2 instance, with Java version 1.7.0_76

Are there any generic reasons as to why this might occur? Any suggestions as to how I can investigate and resolve this?