Some applications will require external resources to be available to the application server during runtime like a JDBC driver or a DLL that contains a native library that the app needs. When this happens what you need to do is navigate to your Window > Preferences > MyEclipse > Application Server preferences, select your application server connector, then click on it's Paths preferences. From there you can append any necessary JARs or Directories to your classpath or library path respectively that are necessary for your app to use in order to run.