Memory corruptions with mod_perl on win32

Hi,

I use Steve Hay's mod_perl binaries with ActiveState perl 5.16
http://people.apache.org/~stevehay/

I see these kind of memory corruptions in the apache log when I put
some serious load on the server via ab.

Attempt to free nonexistent shared string '', Perl interpreter:
0x2a99014 at c:/ws/otrs/Kernel/cpan-lib/CGI/Carp.pm line 399.
Attempt to free nonexistent shared string '', Perl interpreter:
0x2a99014 at c:/ws/otrs/Kernel/cpan-lib/CGI/Carp.pm line 399.
Attempt to free nonexistent shared string '', Perl interpreter:
0x2a99014 at c:/ws/otrs/Kernel/cpan-lib/CGI/Carp.pm line 399.
Attempt to free nonexistent shared string '', Perl interpreter:
0x2a99014 at c:/ws/otrs/Kernel/cpan-lib/CGI/Carp.pm line 399.
[Fri Feb 22 11:23:54 2013] -e: Attempt to free unreferenced scalar: SV
0xe2f7bec, Perl interpreter: 0x2a99014 at
c:/ws/otrs//Kernel/System/Main.pm line 871.
[Fri Feb 22 11:23:54 2013] -e: Attempt to free unreferenced scalar: SV
0xb09712c, Perl interpreter: 0x2a99014 at
c:/ws/otrs//Kernel/System/Main.pm line 336.
[Fri Feb 22 11:23:54 2013] -e: Attempt to free unreferenced scalar: SV
0xc04e32c, Perl interpreter: 0x2a99014 at
c:/ws/otrs//Kernel/System/Main.pm line 336.
[Fri Feb 22 11:23:54 2013] -e: Attempt to free unreferenced scalar: SV
0xd31d04c, Perl interpreter: 0x2a99014 at
c:/ws/otrs//Kernel/System/Main.pm line 336.
[Fri Feb 22 11:25:31 2013] -e: Attempt to free unreferenced scalar: SV
0x10add1f4, Perl interpreter: 0x5d33fdc at
c:/ws/otrs//Kernel/System/Main.pm line 871.
[Fri Feb 22 11:25:31 2013] -e: Free to wrong pool 6f27f08 not 7ce7328
at c:/ws/otrs//Kernel/System/Main.pm line 336.

After this apache restarts itself, which leads to lots of requests failing.

I tried different mod_perl binaries, also very old 2.04 ones with
different perls (Strawberry, Activestate) but I keep hitting similar
issues.

How can I find out what is causing these issues?
--
Mike