Summary
The remote host is missing an update to the system as announced in the referenced advisory FreeBSD-SA-05:03.amd64.asc
Solution
Upgrade your system to the appropriate stable release or security branch dated after the correction date
https://secure1.securityspace.com/smysecure/catid.html?in=FreeBSD-SA-05:03.amd64.asc
Insight
The AMD64 architecture has two mechanisms for permitting processes to access hardware: Kernel code can access hardware directly by reason of its elevated privilege level, while user code can access a subset of hardware determined by a bitmap.
The bitmap which determines which hardware can be accessed by unprivileged processes was not initialized properly.
