Hello Slack and welcome to our forums!
First thing...I'd work out some sort of plan to fix your battery problem. Dim your screen if possible. Turn off WiFi when you aren't using it. Scale down the processor speed. And finally, you may want to invest in another charger or change your docking habits. For instance, when I sit down at my desk, I always cradle my PPC - so it will charge and sync. This prevents the loss of power issues.
As far as the activesync error with the partnership, You can go ahead and delete the partnership. Just back up your sync files folder if you use that option. Delete the partnership AND the files so it's clean and then re-establish. It will then sync all your Outlook data. Then you can enable files and move your files backed up prior to the Pocket PC.
Good luck!