Volley NetworkDispatcher.run。処理されない例外 java.lang.NullPointerException

08-04 06:53:37.430: E/Volley(19221): [983] NetworkDispatcher.run: Unhandled exception java.lang.NullPointerException
08-04 06:53:37.430: E/Volley(19221): java.lang.NullPointerException
08-04 06:53:37.430: E/Volley(19221): at libcore.net.UriCodec.encode(UriCodec.java:132)
08-04 06:53:37.430: E/Volley(19221): at java.net.URLEncoder.encode(URLEncoder.java:57)
08-04 06:53:37.430: E/Volley(19221): at com.android.volley.Request.encodeParameters(Request.java:407)
08-04 06:53:37.430: E/Volley(19221): at com.android.volley.Request.getBody(Request.java:393)
08-04 06:53:37.430: E/Volley(19221): at com.android.volley.toolbox.HurlStack.addBodyIfExists(HurlStack.java:223)
08-04 06:53:37.430: E/Volley(19221): at com.android.volley.toolbox.HurlStack.setConnectionParametersForRequest(HurlStack.java:210)
08-04 06:53:37.430: E/Volley(19221): at com.android.volley.toolbox.HurlStack.performRequest(HurlStack.java:106)
08-04 06:53:37.430: E/Volley(19221): at com.android.volley.toolbox.BasicNetwork.performRequest(BasicNetwork.java:94)
08-04 06:53:37.430: E/Volley(19221): at com.android.volley.NetworkDispatcher.run(NetworkDispatcher.java:105)

プロジェクトでVolleyを使っているのですが、NULLパラメータが原因だと知り、ずっと探していました！（笑）。