diff --git a/Interlace/lib/core/__version__.py b/Interlace/lib/core/__version__.py
index b280975..e8b6b09 100644
--- a/Interlace/lib/core/__version__.py
+++ b/Interlace/lib/core/__version__.py
@@ -1 +1 @@
-__version__ = '1.8.0'
+__version__ = '1.8.1'
diff --git a/Interlace/lib/core/input.py b/Interlace/lib/core/input.py
index b2512e0..cb4a15c 100644
--- a/Interlace/lib/core/input.py
+++ b/Interlace/lib/core/input.py
@@ -21,7 +21,7 @@ class InputHelper(object):
     def readable_file(parser, arg):
         if InputHelper.check_path(parser, arg):
             return open(arg, 'r')  # return an open file handle
-            
+
     @staticmethod
     def check_positive(parser, arg):
         try:
@@ -211,7 +211,7 @@ class InputHelper(object):
             for replacement in replacements:
                 if command.name().find(variable) != -1:
                     new_task = command.clone()
-                    new_task.replace(variable, replacement)
+                    new_task.replace(variable, str(replacement))
                     add_task(new_task, tasks, temp_set)
                 else:
                     add_task(command, tasks, temp_set)