I hit stop over and over, wait, but it wont stop.
What does the walk status say? Does it say it saw the stop request?
What's your page timeout? If it's longer than 60 seconds and some page is actually taking that long you'll need to keep hitting stop every minute until that page finishes.
You could kill the walker child process if it won't quit. You can use "ps auxfw" on linux to easily see the parent-child relationship of processes.