Using the script and configuration as submitted with bug report #6319 (except 4.0.1pl2 --> 4.0.2):

On one machine session_destroy() generates warning about unable to delete session, 
on another machine it causes an invalid operation crash with the following detail:

PHP caused an invalid page fault in
module MSVCRT.DLL at 017f:78002d15.
Registers:
EAX=00000004 CS=017f EIP=78002d15 EFLGS=00010202
EBX=ffffff73 SS=0187 ESP=0063f00c EBP=0063f268
ECX=ffffffff DS=0187 ESI=7fffffff FS=7697
EDX=00000000 ES=0187 EDI=100c24ae GS=0000
Bytes at CS:EIP:
8b 40 fc c3 53 8b 44 24 14 0b c0 0f 85 ce 1c 01 
Stack dump:
78011b4d 0063f278 007638c0 00000000 fffffff2 bff713ee 0000017f bff7ead5 000014ae 00000001 00000008 0400000e 60060000 0063f2a8 78011ae5 00000064

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PS: Both machine are using Win98SE and the version of MSVCRT.DLL that came with PHP4.0.2