diff --git a/src/main/kotlin/com/beust/kobalt/app/remote/GetDependencyGraphHandler.kt b/src/main/kotlin/com/beust/kobalt/app/remote/GetDependencyGraphHandler.kt
index 498baf1d..841650ba 100644
--- a/src/main/kotlin/com/beust/kobalt/app/remote/GetDependencyGraphHandler.kt
+++ b/src/main/kotlin/com/beust/kobalt/app/remote/GetDependencyGraphHandler.kt
@@ -29,7 +29,7 @@ class GetDependencyGraphHandler : WebSocketListener {
     }
 
     override fun onWebSocketError(cause: Throwable?) {
-        Exceptions.printStackTrace(cause)
+        Exceptions.printStackTrace(cause!!)
         throw UnsupportedOperationException()
     }
 
diff --git a/src/main/kotlin/com/beust/kobalt/app/remote/SparkServer.kt b/src/main/kotlin/com/beust/kobalt/app/remote/SparkServer.kt
index dccea702..1ffd448c 100644
--- a/src/main/kotlin/com/beust/kobalt/app/remote/SparkServer.kt
+++ b/src/main/kotlin/com/beust/kobalt/app/remote/SparkServer.kt
@@ -111,7 +111,7 @@ class GetDependenciesHandler : WebSocketListener {
     }
 
     override fun onWebSocketError(cause: Throwable?) {
-        Exceptions.printStackTrace(cause)
+        Exceptions.printStackTrace(cause!!)
         throw UnsupportedOperationException()
     }