hack.So: could not read symbols

[Fernando Apesteguía]

I'm using 9.0-RELEASE.

I downloaded the snapshot "9.0-CURRENT-201012" and tried to build it's
kernel but I get this error:

hack.So: could not read symbols: File in wrong format

file reports this:

ELF 64-bit LSB shared object, x86-64, version 1 (FreeBSD), dynamically
linked, not stripped

I compared this file with the same file generated during the
compilation of the 9.0-RELEASE GENERIC kernel and they are identical.

What's the problem here?

Thanks in advance