I am working on rehauling some of the preset saving functions in Wall Worm. While working on making global setting presets (to accomodate multiple mods) I discovered a limitation in the sizes values can be for INI files. Since I am storing all settings in an INI file, this creates a problem.
Although I discovered this for a not-yet-released set of features, this problem could affect the current release.
If you happen to add too many presets into the VMF exporter preset list, it can cause the presets to stop working altogether. To be safe, try not to add too many VMF Exporter presets until the next release of Wall Worm.
I will hopefully have a fix for this in the next week... but I'm overloaded at the moment with non-3D programming. I'll tackle these ASAP.