The document says,
Snippet from http://www.cisco.com/en/US/docs/security/ips/5.1/configuration/guide/cli/cliEvAct.html
The deny packet inline action is represented as a dropped packet action in the alert. When a deny packet inline occurs for a TCP connection, it is automatically upgraded to a deny connection inline action and seen as a denied flow in the alert. If the IPS denies just one packet, the TCP continues to try to send that same packet again and again, so the IPS denies the entire connection to ensure it never succeeds with the resends.
When a deny connection inline occurs, the IPS also automatically sends a TCP one-way reset, which shows up as a TCP one-way reset sent in the alert. When the IPS denies the connection, it leaves an open connection on both the client (generally the attacker) and the server (generally the victim). Too many open connections can result in resource problems on the victim. So the IPS sends a TCP reset to the victim to close the connection on the victim side (usually the server), which conserves the resources of the victim. It also prevents a failover that would otherwise allow the connection to fail over to a different network path and reach the victim. The IPS leaves the attacker side open and denies all traffic from it.
Deny Connection Inline and Deny Attacker Victim Pair Inline seems to have the same effect at the end, except that "Deny Attacker Victim Pair Inline" has an entry in the "Deny attackes".
I hope this answers your query