Well, from reading her blog and the Closed Circle web site, I think the problem is very likely on the publisher end. And the publisher is... Penguin.
Clearly the rights have not reverted to her, yet, and thus she has little or no control over what is published and available as eBooks. Where she
does have control, she's working to get the old books converted. In at least one series case, that's resulted in a fair amount of re-write. Overall, makes for some interesting reading, especially if you've got any contact with the
writing as a job world.