I've done all hardware tests : lm-sensors, hddtemp, memtest86, cpuburn and kernel/glibc/gcc compilation (anybody know more test? :)).

Problem was solved by using last Gcc-3.3.1 and Glibc-2.3.2 ( but upgrading gcc/glibc in step force me to recompile ALL system, and this is what I'm doing now instead of programming in perl :( ).

Thanks for your replies.

P.S. I will report perlbug as soon as I finish with overall system recompilation.