Probably what happened is after it spawned the processes, your ISP's daemon saw it as a run-away program, and killed it.
On virtual and shared accounts, high-end, cpu-intensive and multi-threaded (real or pseudo) processes are often killed as soon as they start.
Before driving yourself crazy, you might want to ask your ISP if that is the problem. Point them to the script. They can run it, and watch if their daemons kill it. If so, there's probably nothing you can do but switch hosts.
It's been said here time and again, that while many ISP's are now offering MySQL to their customers, programs such as Links (or any high-volume catalog) will cause problems.
Perhaps a comparason -- there was a discussion here on the Raq servers. The company making them says they can host 200 websites.... I couldn't put
http://www.postcards.com on one all to itself.
ISP's count on a customer _not_ using any resources -- except email and maybe some bandwidth (the less the better).
If you are hosting a high-end or high-volume site, you almost always have to move to a dedicated server.