I’d suggest doing it easier. I assume that the resource exists and the file is writable (this might be an issue if we’re speaking about system directories).
public void WriteResourceToFile(string resourceName, string fileName)
{
using(var resource = Assembly.GetExecutingAssembly().GetManifestResourceStream(resourceName))
{
using(var file = new FileStream(fileName, FileMode.Create, FileAccess.Write))
{
resource.CopyTo(file);
}
}
}