Hi everyone, this question is very programming-centric, but it's for a game so I figured I might as well post it here. I'm doing polishing work on a GGJ '11 game because it will be shown at an indie arcade tomorrow afternoon, and they're expecting our final build in the morning. We'd like to have a high score table that displays during attract mode, but since it's Flash (Flixel) it would require some networking, Mochi, or something to keep a record of these scores. Only problem is the machine we'd be running on probably won't have network access. As a quick solution, I thought I'd just write up a dinky little high score server in C#/.NET that could take basic GET requests for submitting scores and getting the score list. We're talking REAL basic, like blocking while waiting for an incoming request, run & forget console app, etc. There's no guarantee that our .swf won't get reloaded, and we'd like the scores to persist, so this server would pretty much exists to keep a safe copy of the scores that the game can add to and request, and occasionally the server will write the scores to a flat text file. But, HttpListener is giving me Error Code 87 'The parameter is incorrect.' Have any idea what I'm doing wrong? Or better yet, am I barking up the wrong tree and missing an obviously simpler solution? This is all I've got so far in my Main(): HttpListener listener = new HttpListener(); listener.Prefixes.Add("http://localhost:66666/"); listener.Start(); The exception happens at listener.Start(); and the stack trace is: at System.Net.HttpListener.AddAllPrefixes() at System.Net.HttpListener.Start() at WOSEBCE_ScoreServer.Program.Main(String[] args) in C:\Users\Michael\Documents\Visual Studio 2010\VS2010 Projects\WOSEBCE_ScoreServer\WOSEBCE_ScoreServer\Program.cs:line 24 at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart()