diff --git a/server.lua b/server.lua
index 879a501..76886d6 100644
--- a/server.lua
+++ b/server.lua
@@ -134,10 +134,11 @@ end
 function processRequests()
     while true do
         local id, msg = rednet.receive "dragon"
-        if msg and msg.cmd then
+        if msg and msg.cmd and msg.uid then
             local ok, r = pcall(processRequest, msg)
 
-			if not ok then r = "ERROR" end
+            if not ok then r = "ERROR" end
+            r.uid = msg.uid
 			
             rednet.send(id, r, "dragon")
         end
diff --git a/util.lua b/util.lua
index 18ae626..cade61b 100644
--- a/util.lua
+++ b/util.lua
@@ -2,13 +2,32 @@ local f = fs.open("conf", "r")
 local conf = textutils.unserialise(f.readAll())
 f.close()
 
+local errors = {
+	matches = function(error, etyp)
+		return error and error[1] == etyp
+	end,
+	error = function(etyp, ...)
+		local ret = {etyp}
+		for _, arg in pairs({...}) do
+			table.insert(ret, arg)
+		end
+		return ret
+	end,
+	missingItems = "EITEMS",
+	noSpace = "ESPACE",
+	noPattern = "EPATTERN",
+	
+}
+
 -- Queries Dragon servers. In a loop.
 local function query(m)
+	local uid = math.random(0, 1000000000)
+	m.uid = uid
 	local msg
 	repeat
     	rednet.broadcast(m, "dragon")
     	_, msg = rednet.receive("dragon", 1)
-	until msg
+	until msg and msg.uid == uid
 	return msg
 end