mciSendString cannot save wave file

[Steve1_rm]

Hello, VS 2008 SP1 I have a created a small application that records and plays audio. However, my application needs to save the wave file to the application data directory on the users computer. The mciSendString takes a C style string as a parameter and has to be in 8.3 format. However, my problem is I can't get it to save. And what is strange is sometime it does and sometimes it doesn't. However, most of the time it failes. However, if I save directly to the C drive it works first time everything. I have used 3 different methods that I have coded below. The error number that I get when it fails is 286."The file was not saved. Make sure your system has sufficient disk space or has an intact network connection"

\[DllImport("winmm.dll",CharSet=CharSet.Auto)\]
        private static extern uint mciSendString(\[MarshalAs(UnmanagedType.LPTStr)\] string command,
                                                 StringBuilder returnValue,
                                                 int returnLength,
                                                 IntPtr winHandle);

        \[DllImport("winmm.dll", CharSet = CharSet.Auto)\]
        private static extern int mciGetErrorString(uint errorCode, StringBuilder errorText, int errorTextSize);

\[DllImport("Kernel32.dll", CharSet=CharSet.Auto)\]
        private static extern int GetShortPathName(\[MarshalAs(UnmanagedType.LPTStr)\] string longPath,
                                                   \[MarshalAs(UnmanagedType.LPTStr)\] StringBuilder shortPath,
                                                    int length);

 // Stop recording
        private void StopRecording()
        {
            // Save recorded voice
            string shortPath = this.shortPathName();
            string formatShortPath = string.Format("save recsound \\"{0}\\"", shortPath);
            uint result = 0;
            StringBuilder errorTest = new StringBuilder(256);
            
            // C:\\DOCUME~1\\Steve\\APPLIC~1\\Test.wav
            // Fails
            result = mciSendString(string.Format("{0}", formatShortPath), null, 0, IntPtr.Zero);
            mciGetErrorString(result, errorTest, errorTest.Length);

            // command line convention - fails
            result = mciSendString("save recsound \\"C:\\\\DOCUME~1\\\\Steve\\\\APPLIC~1\\\\Test.wav\\"", null, 0, IntPtr.Zero);
            mciGetErrorString(result, errorTest, errorTest.Le