diff --git a/lib/galaxy/tools/parameters/__init__.py b/lib/galaxy/tools/parameters/__init__.py
index 2312110130b1..c05063b7d824 100644
--- a/lib/galaxy/tools/parameters/__init__.py
+++ b/lib/galaxy/tools/parameters/__init__.py
@@ -44,7 +44,7 @@ def visit_input_values( inputs, input_values, callback, name_prefix="", label_pr
         else:
             args = {
                 'input'             : input,
-                'value'             : input_values[ input.name ],
+                'value'             : input_values.get( input.name ),
                 'prefixed_name'     : "%s%s" % ( name_prefix, input.name ),
                 'prefixed_label'    : "%s%s" % ( label_prefix, input.label )
             }
diff --git a/lib/galaxy/tools/parameters/basic.py b/lib/galaxy/tools/parameters/basic.py
index 715e1993ceb4..9d8822a40811 100644
--- a/lib/galaxy/tools/parameters/basic.py
+++ b/lib/galaxy/tools/parameters/basic.py
@@ -726,7 +726,11 @@ def from_html( self, value=None, trans=None, other_values={} ):
         return self._get_value()
 
     def _get_value( self ):
-        return url_for( self.value, qualified=True )
+        try:
+            return url_for( self.value, qualified=True )
+        except Exception as e:
+            log.debug( 'Url creation failed for "%s": %s', self.name, e )
+            return self.value
 
     def to_dict( self, trans, view='collection', value_mapper=None, other_values={} ):
         d = super( BaseURLToolParameter, self ).to_dict( trans )