diff --git a/src/plugins/xml.lua b/src/plugins/xml.lua
index f1f9147..20a22da 100644
--- a/src/plugins/xml.lua
+++ b/src/plugins/xml.lua
@@ -95,6 +95,9 @@ local function findExpressions(text)
 end
 
 local function convertValue(value, scope)
+    if type(value) ~= "string" then
+        return value
+    end
     if value:sub(1,1) == "\"" and value:sub(-1) == "\"" then
         value = value:sub(2, -2)
     end