Portsnap problem: "gunzip: unknown compression format"

[Gonzalo Nemmi]

I've been getting this for the last three days even though there where no 
changes at all in my system.

root at inferna:~ # portsnap fetch update
Looking up portsnap.FreeBSD.org mirrors... 2 mirrors found.
Fetching snapshot tag from portsnap1.FreeBSD.org... done.
Fetching snapshot metadata... done.
Updating from Wed Jan  7 17:20:01 ARST 2009 to Sat Jan 10 13:26:38 ARST 2009.
Fetching 3 metadata patches.. done.
Applying metadata patches... done.
Fetching 0 metadata files... done.
Fetching 258 
patches.....10....20....30....40....50....60....70....80....90....100....110....120....130....140....150....160....170....180....190....200....210....220....230....240....250.... 
done.
Applying patches... done.
Fetching 29 new ports or files... gunzip: unknown compression format
snapshot is corrupt.
root at inferna:~ # which gunzip
/usr/bin/gunzip
root at inferna:~ #

Is anyone getting the same message?
Any hints on what could be the mos likely cause?

Thanks in advanced.
-- 
Blessings
Gonzalo Nemmi