Help! Portsnap won't work on freeBSD 10.0-CURRENT/amd64! look: tINDEX.new: File too large

   Hello,
   since several days now I receive on FreeBSD 10.0-CURRENT/amd64 boxes
   this message:
   --
   Looking up portsnap.FreeBSD.org mirrors... 5 mirrors found.
   Fetching snapshot tag from portsnap1.FreeBSD.org... done.
   Fetching snapshot metadata... done.
   look: tINDEX.new: File too large
   Portsnap metadata appears bogus.
   Cowardly refusing to proceed any further.
   --
   It came out of nowhere while I was updating the same day (it was
   Thursday or Friday last week) successfully on the same boxes.
   I didn't find anything about such an error in the list or on the web,
   so I'm confused. On FreeBSD 9.0-BETA3 at a box besides one of the
   failing ones everything run smooth.
   I already deleted /var/db/portsnap and tried to recreate everything. I
   checked the clock (some similar weird errors reported problems with a
   clock gain). But everything is all right - execpt that FBSD 9.0 works,
   and 10.0 not.
   Thanks in advance,
   Oliver