Pclos has an ia32-libs package which installs 32-bit libraries (mainly for Skype, I'm told) in /opt/libs32/. This package contains libraries needed by wine-wow64. It also contains a copy of libwine.so.1, one of the main libraries supplied by wine-wow64, which installs it in /usr/lib/.
The result is that two copies of this library get installed by wine, and ldconfig prefers the one in /opt/libs32/ over the one in /usr/lib/, causing wine to become confused over its version number and possibly causing some applications to segfault.
Unless ia32-libs can be upgraded every time one of the packages which owns one one of its libs is upgraded, we have a problem here, especially as it is not necessarily obvious to packagers that this other package contains a copy of a library they're packaging.
We need an authoritative steer around this problem, as it breaks Wine, and potentially any other application that needs 32-bit libs on a 64-bit system.
One suggestion I can think of is add the real 32-bit packages which own the files in ia32-libs to the 64-bit repo (in a separate section, perhaps?) and then make ia32-libs a meta package to install them all, but maybe there's a good reason not to do that.