She was the Gnome Foundation head honcho and co-lead of the Outreach Project for Women (the other co-lead was apparently from Red Hat, not Gnome) during the time period in question. Of course she was responsible. No doubt other people screwed up too, but according to the official FAQ they simply didn't have enough admin staff to keep up with the accounting work generated by the OPW and that too was her responsibility, because that's what being in charge means. Incidentally, she resigned about a fortnight before that announcement.

They weren't just bad at collecting money either - if I'm understanding their announcements and FAQ correctly, the OPW came with contractual deadlines for Gnome to pay participants but no similar deadlines for sponsors to pay Gnome, which is why they had to prioritize OPW payments over everything else.