kernel: rtfree: 0x******** has 1 refs

Periodically, I get the following message:
Dec 11 10:03:43 stats kernel: rtfree: 0xc1f2cbb8 has 1 refs
they appear randomly and I can not understand why...
I tried to search with google, but nothing substantial I did not find.

uname -a
FreeBSD stats.pcb 7.0-RELEASE-p6 FreeBSD 7.0-RELEASE-p6 #1: Mon Dec  8 08:42:22 EET 2008     m0ps@stats.pcb:/usr/obj/usr/src/sys/STATS  i386

FreeBSD instaled on Vmware ESXi update 3 server with default hardware.

any ideas?
This should come from src/sys/net/route.c
Is it panicking?
Are you running many daemons related to networking?