She sounds like a nightmare. Has proper notice of the EC meetings been given? Whale is right – when notice is given owners with entitlements exceeding 1/3 can oppose any motion before the meeting is held/decision is made.
At the next AGM make sure you attend and that you and at least one other owner nominates for the EC. If you can't attend you can nominate in writing. Set the membership of the EC at 3, that way she won't be able to unilaterally make decisions, even numbers are not a good idea on the EC. If that is not possible for whatever reason, you could consider limiting the decisions that can be made by the EC, which is a standard resolution at the AGM. Of course that can limit the EC's operation but you can be creative. For example, it could provide that applications can't be lodged with the CTTT without a certain vote of the EC, i.e. more than 1. CTTT applications cost money!