Hi,
as I mentioned I've tried to crawl your website successfully (I stopped the process at 15,000 urls and it was counting), so this is probably some specific server configuration issue. And hard to determine that exactly without being able to test at your host. The only thing I noticed is that your site is running eAccelerator: if you can try to disabling and crawl the site, that will at least ensure the problem is not at this side.