Hi to all!
 I've tried all the new versions of php (from 4.0.4pl1 to 4.0.7pre) and all have given me the same problem:
 in high traffic situations few apache children crash causing the system to go down. The only way to solve the problem is to power down the machine (no safely reboot command of linux... the console is blocked...).

 This problem has presented only after 4.0.5 (but 4.0.4pl1 has given problem with Imap).
 To solve the problem i recompiled apache 1.3.20 with php 4.0.3pl1 and all now is working correctely.

The software i used is:
 - Apache 1.3.20
 - Php 4.0.5, 4.0.6, 4.0.7pre
The configure line is:
 ./configure --enable-imap --enable-mysql --with-mysql --with-apache=../$APACHE --with-imap
--without-xml --enable-track-vars --enable-memory-limit=yes --with-zlib=/usr
--with-gd=/usr/local --with-jpeg-dir=/usr --with-png-dir=/usr --enable-magic-quotes

Thank for help,
Denis

PS: I'm not able to create a gdb backtrace because when i try to attach the gdb to the process, gdb crashes too!