This isn't directly related to uc_civicrm, but I thought I'd post this here for the benefit of anyone using uc_civicrm that might be having problems with it. We used to use uc_civicrm, then we started using the script that comes with CiviCRM called ContributionProcessor.php (in the bin/ directory), which pulls data down from PayPal and/or Google Checkout manually rather than relying on IPN or notifications. One benefit of this is that for us it obviates the needs for uc_civicrm. We use it for other things but it only required a simple patch to recognize transactions from PayPal that are from Ubercart and mark them in CiviCRM with a contribution type of "Store" so that we can easily identify then and run reports, etc.... something like:
if ( preg_match('/^Order \d+ at/', $params['transaction']['source']) ) {
// 8 is the db ID of type "Store"... careful it doesn't change
$params['transaction']['contribution_type_id'] = '8';
}Basically, you can use this script to only pull down transaction history from PayPal or Google Checkout, and to only create new contacts/contributions in CiviCRM for Ubercart orders. The script doesn't add the user to a "Purchasers" group, but it does enter any and all information PayPal sends, which might even include an address.
It does require setting up a period cron job to run the script. Just thought I'd throw this out there as a viable option and alternative to uc_civicrm.