packet loss in the network

When I ping the default gateway and the novell servers on the network, Often it is experienced a packet loss of 25% somethimes 50%. Previously the node was on a shared hub, now I connected it on a dedicated 10 base t port on catalyst 5500 switch, still its experiencing the packet loss, NIc is 3Com 10/100 Ethernet, the settings for the NIC card is set to 10 Mbps, Duplex Auto
No other host on this segment is having such problem. What might be the problem? Any solutions higly appreciated