I've used Software.
Current bid was $6.5
My bid was $8
Sniper was ACTIVATED (checkbox enabled)
Bid time was changed from 6 sec to 5 sec

And... it didn't put my bid!!! $6.5 bid won. OMG =) What's happened, guys?

Thx

Sniping does not guarantee winning. You have to meet eBay's or seller's requirements too.

You can check "My Status" field for more information on what was the reason.

If you want me to check it, please provide the item number with your question.

OMG! I removed it from myibay software. Ebay product ID is 220557124765. After 21h I'll see what happen with another bid 220557124765

You could always add it back.

Anyway, I checked it and see the following reason:
"Your PayPal account is not linked to your eBay account"

This a restriction which was set by the seller on this listing.
Please check the following forum thread for more information about it:
http://www.myibay.com/forums/viewtopic/647/your-paypal-account-is-not-linked-to-your-ebay-account/

Thx. Added.