JScript try catch network exception

I'm writing a script that stores database backup files to multiple locations. In addition, the data is stored on a NAS, which is normally accessible. If this is not the case, the error message is to be intercepted.
I tried it this way:

wshshell = WScript.CreateObject("WScript.Shell");
fso = WScript.CreateObject("Scripting.FileSystemObject");

SetupPath = WScript.arguments(0);
if (fso.FileExists(SetupPath))
{
//Load setup JSON
SetupFile = fso.OpenTextFile(SetupPath, 1, true, 0);
eval(SetupFile.ReadAll());

// Parse setup configuration from JSON
...
BackupPath = Setup["BackupPath"];
FilesForBackup = Setup["FilesForBackup"];
NASBackupPath = Setup["NASBackupPath"];
...

CreateNewBackupFiles();

Log("Script was successfully executed.");
}
else
{
Log("Script was not successfully executed.");
}

/* Creates a new compressed database backup */
function CreateNewBackupFiles()
{
tempfile = fso.GetTempName();

file = fso.GetFile("C:\\Program\\7-Zip\\7z.exe");
rarexe = file.ShortPath;

script = rarexe + " a -r " + tempfile + " " + FilesForBackup;
wshshell.Run(script, 0, true);

fso.CopyFile(tempfile, BackupPath + PrefixBackupFile + "backup.7z");

//Save to NAS
if(NASBackupPath!="")
{
try
{
fso.CopyFile(tempfile, NASBackupPath);
}
catch(err)
{
Log("Path \"" + NASBackupPath + "\" not available.");
}
}
fso.DeleteFile(tempfile, true); //delete tempfile
}

/* Saves a log in "Debug.Log" */
function Log(msg)
{
fs = WScript.CreateObject("Scripting.FileSystemObject");
a = fs.OpenTextFile("Debug.log", 8, true, 0);
line = "[" + CurrentTime()+ "] ";
line += "[" + WScript.ScriptName + "] ";
line += "[" + msg + "]";
a.WriteLine(line);
}
Nevertheless, errors continue to be issued. I´m using the Script on Windows XP SP3. Is there a possibility to catch this error with javascript?

thanks

I have found the error. The error came from the "Log". First, not every time a new "File System object" must be created. It can be simply used the object "fso". In addition, the open text file must be closed at the end of the function. Here is the correction:

function Log(msg)
{
a = fso.OpenTextFile("Debug.log", 8, true, 0);
line = "[" + CurrentTime()+ "] ";
line += "[" + WScript.ScriptName + "] ";
line += "[" + msg + "]";
a.WriteLine(line);
a.Close();
}