Seeing as how I know nothing much about msi I thought I'd just point out the error and ask someone more knowledgeable to do something about it.
Basically on msiexec a VBA6.msi:
dialog.c - msi_dialog_oncreate includes dialog->default_font = msi_dup_property (.., "DefaultUIFont");
Later on that default font can be referenced without testing if it is non-null
In my particular case it is null (because the property is not found).
Presumably if msi_dup_property returns null then some other default should be used, e.g. MS Shell Dlg.
Any comments? Anyone volunteering to fix it?