Are you using VLANs? If you have VLANs configured on your network then maybe the VLANs setting do not match on the switches.
Is the 2724 running in managed or unmanaged mode - I'm assuming it is in managed mode if you can see link status from 2724? Try pinging the 2724 management IP address from the Cisco switch directly connected to it.
Also try connecting two hosts directly to the 2724 and see if they can talk to each others. If they can then perhaps there is some configuration problem on the port between the 2724 and the Cisco switch. At that point we will need to see what is configured on the 2724 (if it is managed mode) and what's configured on the Cisco switch.
You said that the status on the link shows that it is "1000 Full" from the 2724 perspective, can you see what the Cisco switch is reporting the status of the link to be? I'm assuming both Cisco and PowerConnect ports are configured to "auto-negotiation".