I have the following environment:
- XP SP3
- Rainlendar Lite 2.9
with older version, I could sync both ways (Google > Rainlendar and Rainlendar > Google), but after installing this version I'm having trouble to sync from Google > Rainlender (if I create a new event, after clicking Sync, it showed a green progress bar then the DOS box disappeared, but the Rainlendar did not update, but if I create an event in Rainlendar, then Google got updated), is there something I'm missing?

Welcome to the forum, michaelbr.
You say you are using Lite, but Lite is not support sync with Google.
So maybe the problem is in your sync app instead of in Rainlendar.

I'm pretty sure that the sync app came with Lite, actually I was mistaken with the sync, the sync didn't show up right away, but after 1 day or shut down (I'm not sure which one, but the next day, the change showed up in Rainlender).