Single backend crashes if postmaster running

Name :Ronald Kuczek
Email address :ronald@breitenbach-it.de

System Configuration
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Architecture : Intel Pentium

Operating System : Linux i586 GNU, Windows NT

PostgreSQL version : PostgreSQL-7.0 beta 5

Compiler used :gcc (Linux),cygwin b-20 (NT)

FULL description of problem:
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I try to port PostgreSQL on Windows 9x. On 9x newly created backend (if postmaster running) crashes, single backend (no postmaster) - no problem.
I have tried to start on NT postgres -p template1 I become error message too:

[main] C:\usr\local\pgsql\bin\postgres.exe 1015 (0) handle_exceptions: Exception
: STATUS_ACCESS_VIOLATION
[main] postgres 1015 (0) handle_exceptions: Dumping stack trace to postgres.exe.
core

on Linux I become error message(identical conditions - running postmaster -i and command postgres -p template1):

Segmentation fault.

From my postgres.map and postgres.exe.core files - it happened in pq_flush function, but I don't know yet why...