Handle gstreamer audio init better

Vocaluxe/Lib/Sound/Playback/GstreamerSharp/CGstreamerSharpAudio.cs

@@ -17,6 +17,7 @@
 
 using Gst;
 using System;
+using Vocaluxe.Base;
 
 namespace Vocaluxe.Lib.Sound.Playback.GstreamerSharp
 {
@@ -26,13 +27,20 @@ namespace Vocaluxe.Lib.Sound.Playback.GstreamerSharp
         {
             if (_Initialized)
                 return false;
+
 #if ARCH_X86
-            var gstreamerEnvVar = Environment.GetEnvironmentVariable("GSTREAMER_1_0_ROOT_X86", EnvironmentVariableTarget.User);
+            const string varName = "GSTREAMER_1_0_ROOT_X86";
 #endif
 #if ARCH_X64
-            var gstreamerEnvVar = Environment.GetEnvironmentVariable("GSTREAMER_1_0_ROOT_X86_64", EnvironmentVariableTarget.User);
+            const string varName = "GSTREAMER_1_0_ROOT_X86_64";
 #endif
-            var dllDirectory = gstreamerEnvVar + "bin\\";
+            string gstreamerEnvVar = Environment.GetEnvironmentVariable(varName, EnvironmentVariableTarget.User);
+            if (gstreamerEnvVar == null)
+            {
+                CLog.LogError("Gstreamer not found! Make sure you installed it correctly and if it set the environment variable '" + varName + "'!", true);
+                return false;
+            }
+            string dllDirectory = gstreamerEnvVar + "bin\\";
             COSFunctions.AddEnvironmentPath(dllDirectory);
 
             Application.Init();