I have double checked and confirmed that the 2724 does not have spanning tree at all.  I did some reading in a Cisco troubleshooting article and it suggested the same thing of enabling the BPDU filter.  Keep us updated and let us know if that setting helps.
We are a Cisco shop, but we commonly use 2724 switches when we need a low cost unmanaged gb switch. It is useful when we have a large group of servers all on the same VLAN. We disable BPDU guard on the Cisco port since there is very little chance of creating a loop. The 2724 will only connect to one switch using only one link. In any case, we now have a Cisco access layer with fabric extenders. These fabric extenders are hard-coded with BPDU guard so I can't disable it. As soon as I connect a 2724 to it, the Cisco switch puts the port into err-disabled state because it received a BPDU on that port. I'd like to disable spanning tree on the 2724 but I don't see an option when browsing through the web management. Am I missing something here?
Disable spanning tree on 2724?