error packets with syslog

[Claus Rosenberger]

we use two vpn gateways with ipsec and two terminal servers behind it.

one server write syslog entries to the other subnet accross the vpn. these
packets marked as error packets in the first gateway.

TerminalServer-1
          |
Gateway-1
          |
Gateway-2
          |
Destination for Logging

TerminalServer-1 has following syslog.conf entry :

 *.*   @10.2.4.6

Gateway-1 show following interface statistic, if syslog-rule is active :

eth0      Link encap:Ethernet  HWaddr 00:B0:D0:68:74:3E
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:47798 errors:0 dropped:0 overruns:0 frame:0
          TX packets:336401 errors:0 dropped:0 overruns:0 carrier:0
          collisions:231 txqueuelen:100
          Interrupt:5

eth1      Link encap:Ethernet  HWaddr 00:03:47:42:03:A7
          inet addr:10.1.1.1  Bcast:10.1.255.255  Mask:255.255.0.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:764146 errors:509636 dropped:509636 overruns:20263
          frame:0          TX packets:45921 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          Interrupt:11 Memory:fe000000-fe020000

ipsec0    Link encap:Ethernet  HWaddr 00:B0:D0:68:74:3E
          UP RUNNING NOARP  MTU:16260  Metric:1
          RX packets:17547 errors:0 dropped:5 overruns:0 frame:0
          TX packets:17639 errors:2030 dropped:0 overruns:0 carrier:2030
          collisions:0 txqueuelen:10

if i stopped the syslog-rule on TerminalServer-1 i didn't get any error
packets. if the rule is active i got a lot of them. why ?
informations of servers :

TerminalServer-1 : RedHat 7.0 with delivered RedHat-Kernel
Gateway-1 : RedHat 7.1 with Kernel 2.4.3 and FreeSWan 1.9.