no g_assert_warning after upgrading to 2.6.1-1

[Marco <mscholtn xs4all nl>]

After upgrading gtkmm to 2.6.1-1 on windows xp using Cedric Gustin's  
installer i get the following warning when running my program:

The procedure entry point g_assert_warning could not be located in the  
dynamic link library libglib-2.0.0.dll

execution stops after that
The dll is present and in the path.

I then tried to run the gtkmm demo and got the same warning.
Uninstalling gtk+ and gtkmm and reinstalling did not help.

What could be wrong?

--
Marco Scholten