diff --git a/server/vr/server/forms.py b/server/vr/server/forms.py
index aa5f3be3..9f66e49a 100644
--- a/server/vr/server/forms.py
+++ b/server/vr/server/forms.py
@@ -1,3 +1,5 @@
+import xmlrpclib
+
 from django import forms
 from django.conf import settings
 from django.contrib.auth import authenticate
@@ -21,18 +23,29 @@ def clean_config_yaml(self):
         config_yaml = self.cleaned_data.get('config_yaml', None)
         if config_yaml:
             try:
-                yaml.safe_load(config_yaml)
+                data = yaml.safe_load(config_yaml)
             except:
                 raise forms.ValidationError("Invalid YAML")
+
+            try:
+                xmlrpclib.dumps((data,), allow_none=True)
+            except Exception as e:
+                raise forms.ValidationError("Cannot be marshalled to XMLRPC: %s" % e)
         return config_yaml
 
     def clean_env_yaml(self):
         env_yaml = self.cleaned_data.get('env_yaml', None)
         if env_yaml:
             try:
-                yaml.safe_load(env_yaml)
+                data = yaml.safe_load(env_yaml)
             except:
                 raise forms.ValidationError("Invalid YAML")
+
+            try:
+                xmlrpclib.dumps((data,), allow_none=True)
+            except Exception as e:
+                raise forms.ValidationError("Cannot be marshalled to XMLRPC: %s" % e)
+
         return env_yaml