On Win32, optimized build (firefox) with profile fails with an error from cvpack

I tried to build an optimized build with symbols so that I can debug.
(I'm trying to solve a problem that only manifests itself in optimized
builds). I used 'enable-optimize' along with 'MOZ_PROFILE=1' in my
mozconfig file. However, when building gklayout.dll, I got the following
error:

***** cvpack INTERNAL ERROR, exception code = 0xc0000005 *****

LINK : warning LNK4027: CVPACK error
make[1]: *** [gklayout.dll] Error 66
make[1]: *** Deleting file `gklayout.dll'
make[1]: Leaving directory `/cygdrive/f/moz/builds/fb.opt/layout/build'
make: *** [all] Error 2


MSDN has several articles about *old' (visual c 5.0 or earlier) versions
of cvpack not being able to handle more than 64k symbols. However, I'm
not supposed to come across this problem because I have VC++ 6.0

It'd be nice if somebody could help me with this.

Jungshik