I don't have a node now (shame on me, I wasn't able to compile the other day).
From what Rik8119 says, it seems that the longest chain is invalid, because the blocks have nVersion=2
> I can only run version x.8.3.
There's your problem then, once bip66 was activated, all miners need to validate it and produce nVersion=3 blocks.
From what it's in the release notes you need 0.8.6.2, see https://github.com/freicoin/freicoin/commit/808ee0ecab1e075c0835e74cd85627d3e5b1dd1d