Problems Networking Red Hat AS 3

I have RH Advanced Server running on a box I use for development.
That's why it has AS - it's a copy (sort of) of the production server.

Anyway, I am getting the following error message displayed on the
console every few seconds:

128.104.17.179 sent an invalid ICMP type 11, code 0 error to a
broadcast: 128.104.19.255 on eth0

Also, the networking gets "tired". Every once in a while, I get very,
very slow network access until I login at the console and do:

$ service network restart

Then it's fine again for a while. I'm using the EPIC100 module with a
Standard Microsystems Corp [SMC] 83C170QF (rev 8) internet controller.

Output from ifconfig:

eth0 Link encap:Ethernet HWaddr 00:E0:29:34:B6:81
inet addr:128.104.17.179 Bcast:128.104.19.255
Mask:255.255.252.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:18297857 errors:1451991 dropped:1470359 overruns:0
frame:0
TX packets:366758 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:2717406745 (2591.5 Mb) TX bytes:66574728 (63.4 Mb)
Interrupt:10 Base address:0xd800