If elections are how the PTO's by-laws stipulate that vacancies are to be filled, those board positions will be vacant if the process has not been followed. You may want to check the by-laws to see if vacancies can be filled via nominations from the floor when the PTO next convenes.

If the remaining members of the 2009-2010 board choose not to hold any general meetings, despite the requirement to do so in the by-laws, the general membership may raise a point of order with the PTO president (although scheduling the next meeting should have been done prior to adjourning the last general meeting).

[re-posted for EllenVP from comments section]
I have been the VP for five years and this year I worked with a new board including a new President. We had only 1 General meeting the whole school year. There is 2 weeks of school left and there is not a last meeting scheduled for 2009-2010 elections. Can the new board assume their positions for next year and not have a meeting? According to our By-Laws we should. If they refuse, then what?