It's not a Perl-related problem, chb should be on the right path. Googling a bit, I see that this ERESTARTNOHAND has to do with the way signals interfere with system calls, maybe you can unfog it a little reading this.

It's probable that the web server sets some alarm that intervenes during the select syscall, interrupting it and trying to make the whole stuff restart. Probably you'd better search more in Linux kernel mailing lists or fora to see if this problem (if there's a problem!) has been addressed in some recent version of the kernel.