I raised the memory to 512 MB but now the program stop responding at all.
There are many free tools which capable of producing 50,000 pages site map, I paid you to have a better tool. but it seems it can't work even as good as free software.
I can't generate a site map with more than 42,000 pages. it just crashes. I use a dedicated server with 4GB Ram, so there shouldn't be any problem with CPU or Ram.