diff --git a/src/Mono.WebServer.Fpm/ChildrenManager.cs b/src/Mono.WebServer.Fpm/ChildrenManager.cs
index e8639c7..0c688b3 100644
--- a/src/Mono.WebServer.Fpm/ChildrenManager.cs
+++ b/src/Mono.WebServer.Fpm/ChildrenManager.cs
@@ -16,11 +16,11 @@ namespace Mono.WebServer.Fpm
 				try {
 					if (!child.Process.HasExited)
 						child.Process.Kill();
-				}
-				catch (InvalidOperationException) {
+				} catch (InvalidOperationException) {
 					// Died between the if and the kill
 				}
 			}
+			children.RemoveAll(child => child.Process.HasExited);
 		}
 
 		public static void TermChildren()
@@ -33,14 +33,20 @@ namespace Mono.WebServer.Fpm
 					// Died between the if and the kill
 				}
 			}
+			children.RemoveAll (child => child.Process.HasExited);
 		}
 
 		public static void StartChildren(FileInfo[] configFiles, ConfigurationManager configurationManager)
 		{
+			if (configFiles == null)
+				throw new ArgumentNullException ("configFiles");
+			if (configurationManager == null)
+				throw new ArgumentNullException ("configurationManager");
 			foreach (var fileInfo in configFiles) {
 				Logger.Write(LogLevel.Debug, "Loading {0}", fileInfo.Name);
 				var childConfigurationManager = new ChildConfigurationManager();
-				childConfigurationManager.LoadXmlConfig(fileInfo.FullName);
+				string fullName = fileInfo.FullName;
+				childConfigurationManager.LoadXmlConfig(fullName);
 				string user = childConfigurationManager.User;
 				string fastCgiCommand = configurationManager.FastCgiCommand;
 
@@ -48,13 +54,13 @@ namespace Mono.WebServer.Fpm
 				if (Platform.IsUnix) {
 					if (String.IsNullOrEmpty(user)) {
 						Logger.Write(LogLevel.Warning, "Configuration file {0} didn't specify username, defaulting to file owner", fileInfo.Name);
-						user = UnixFileSystemInfo.GetFileSystemEntry(fileInfo.FullName).OwnerUser.UserName;
+						user = UnixFileSystemInfo.GetFileSystemEntry(fullName).OwnerUser.UserName;
 					}
 
-					child = Spawner.RunAs(user, Spawner.SpawnChild, fileInfo, fastCgiCommand);
+					child = Spawner.RunAs(user, Spawner.SpawnChild, fullName, fastCgiCommand);
 				} else {
 					Logger.Write(LogLevel.Warning, "Configuration file {0} didn't specify username, defaulting to the current one", fileInfo.Name);
-					child = Spawner.SpawnChild(fileInfo, fastCgiCommand);
+					child = Spawner.SpawnChild(fullName, fastCgiCommand);
 				}
 				children.Add(child);
 			}
diff --git a/src/Mono.WebServer.Fpm/Spawner.cs b/src/Mono.WebServer.Fpm/Spawner.cs
index 54cfa29..3627cbd 100644
--- a/src/Mono.WebServer.Fpm/Spawner.cs
+++ b/src/Mono.WebServer.Fpm/Spawner.cs
@@ -9,18 +9,26 @@ namespace Mono.WebServer.Fpm
 	{
 		public static T RunAs<T, T1, T2>(string user, Func<T1, T2, T> action, T1 arg0, T2 arg1)
 		{
+			if (user == null)
+				throw new ArgumentNullException ("user");
+			if (action == null)
+				throw new ArgumentNullException ("action");
 			using (var identity = new WindowsIdentity(user))
 			using (identity.Impersonate())
 				return action(arg0, arg1);
 		}
 
-		public static ChildInfo SpawnChild(FileInfo fileInfo, string fastCgiCommand)
+		public static ChildInfo SpawnChild(string fullName, string fastCgiCommand)
 		{
+			if (fullName == null)
+				throw new ArgumentNullException ("fullName");
+			if (fastCgiCommand == null)
+				throw new ArgumentNullException ("fastCgiCommand");
 			var info = new ChildInfo {
 				Process = new Process {
 					StartInfo = new ProcessStartInfo {
 						FileName = fastCgiCommand,
-						Arguments = String.Format("--config-file {0}", fileInfo.FullName),
+						Arguments = String.Format("--config-file \"{0}\"", fullName),
 						UseShellExecute = true
 					}
 				}