Hi jbt9955,
The generation of the "Blocked by Seller" response to certain snipes actually isn't due to an error on Auction Sniper's end - it is returned when we are unable to place a bid on your behalf because eBay notifies us the bid attempt was blocked by the seller. I clicked the "View Confirmation" button next to your most recent snipe that failed for this reason and found that the following message was returned when your bid was blocked:
This seller has set buyer requirements for this item and only sells to buyers who meet those requirements.
You are unable to bid on or buy this item because:
You either don't have a PayPal account or your PayPal account is not linked to your eBay account.
We encourage you to register with PayPal - it is the fast, easy and safe way to pay. Register with PayPal | Already have a PayPal account?
I believe Rick is spot on with his assessment that you will need to follow the instructions in the thread he provided a link to above. It sounds like there was an error on eBay's end that caused your Paypal account to become un-linked to your eBay account, and that your bid on this item was rejected because the seller only accepts bids from buyers whose Paypal accounts are linked to their eBay accounts.
If you have any additional questions or concerns, please feel free to contact our customer support team by completing the web form on the following page of our site: http://support.auctionsniper.com
-Mike