Hi Robert,
To answer your questions:
1. This is an upgrade. I haven't yet tried uninstalling and reinstalling the plugin, didn't seem to me it would solve a token replacement issue, but I can do it anyway.
2. I've had query issues with this plugin in the past (mostly queries not supported by the database engine), but it's the first time I've encountered this one.
3. I have to get back to you on this later if you need specifics, but one of the situations that triggers this error is when running a cron job (initiated by a crontab script rather than an HTTP request to WordPress).
Thanks!