diff --git a/public/java/src/org/broadinstitute/sting/utils/exceptions/UserException.java b/public/java/src/org/broadinstitute/sting/utils/exceptions/UserException.java
index 6b97f8f9f..c1f408bc7 100755
--- a/public/java/src/org/broadinstitute/sting/utils/exceptions/UserException.java
+++ b/public/java/src/org/broadinstitute/sting/utils/exceptions/UserException.java
@@ -352,6 +352,9 @@ public class UserException extends ReviewedStingException {
     }
 
     public static class CannotExecuteQScript extends UserException {
+        public CannotExecuteQScript(String message) {
+            super(String.format("Unable to execute QScript: " + message));
+        }
         public CannotExecuteQScript(String message, Exception e) {
             super(String.format("Unable to execute QScript: " + message), e);
         }
diff --git a/public/scala/src/org/broadinstitute/sting/queue/util/ScalaCompoundArgumentTypeDescriptor.scala b/public/scala/src/org/broadinstitute/sting/queue/util/ScalaCompoundArgumentTypeDescriptor.scala
index 0d8edc25d..54e89ec58 100644
--- a/public/scala/src/org/broadinstitute/sting/queue/util/ScalaCompoundArgumentTypeDescriptor.scala
+++ b/public/scala/src/org/broadinstitute/sting/queue/util/ScalaCompoundArgumentTypeDescriptor.scala
@@ -28,6 +28,7 @@ import collection.JavaConversions._
 import org.broadinstitute.sting.queue.QException
 import java.lang.Class
 import org.broadinstitute.sting.commandline.{ArgumentMatches, ArgumentSource, ArgumentTypeDescriptor, ParsingEngine}
+import org.broadinstitute.sting.utils.exceptions.UserException
 import java.lang.reflect.Type
 
 /**
@@ -75,6 +76,8 @@ class ScalaCompoundArgumentTypeDescriptor extends ArgumentTypeDescriptor {
   
   def parse(parsingEngine: ParsingEngine, source: ArgumentSource, classType: Class[_], argumentMatches: ArgumentMatches) = {
     val componentType = ReflectionUtils.getCollectionType(source.field)
+    if (componentType == classOf[java.lang.Object])
+      throw new UserException.CannotExecuteQScript("Please also include a @ClassType(classOf[<primitive type>]) annotation on field: " + source.field + ". Example: @ClassType(classOf[Double]). The scala generic type for the field was subjected to java/scala type erasure and is not available via reflection.")
     val componentArgumentParser = parsingEngine.selectBestTypeDescriptor(componentType)
 
     if (classOf[Seq[_]].isAssignableFrom(classType)) {