Try this:

 MagmaSession initialize

and then run your upgrade.

I've seen this error a couple of times, now I think what's happening
is that the class-initialization for MaObjectBuffer got run sometime
_after_ MagmaSession.  Under normal loading procedures that would not
happen, but if a new version of Ma object serialization was loaded
after Magma, it could happen.

Let me know,
 Chris

On Sun, Nov 28, 2010 at 3:50 PM, Facundo Vozzi <facundov79@gmail.com> wrote:
> Sorry, I forgot attach the error. There you go.
> Thanks,
> Facu
>
>
> On Sun, Nov 28, 2010 at 2:57 PM, Chris Muller <ma.chris.m@gmail.com> wrote:
>>
>> What error?  Screenshot?
>>
>> On Fri, Nov 26, 2010 at 3:17 PM, Facundo Vozzi <facundov79@gmail.com>
>> wrote:
>> > Hi Chris,
>> > I did it but I'm getting the error that adjunt in the screnshot. Do you
>> > know
>> > what I'm doing wrong?
>> > Thanks you,
>> > Facundo
>> > On Fri, Nov 26, 2010 at 3:33 PM, Chris Muller <asqueaker@gmail.com>
>> > wrote:
>> >>
>> >> Hi Facundo, please use the "Magma upgrader" package available on the
>> >> "Magma tester" project of squeaksource.
>> >>
>> >> After loading it:
>> >>
>> >>  (MagmaUpgrader source: '/path/to/old/repository') compressTo:
>> >> '/path/to/upgraded/repository'
>> >>
>> >>  - Chris
>> >>
>> >> On Fri, Nov 26, 2010 at 6:54 AM, Facundo Vozzi <facundov79@gmail.com>
>> >> wrote:
>> >> > Hi,
>> >> > how is the way for upgrade my magma repository from version 12
>> >> > to version 14
>> >> > in order to use it with the version 1.2a1 of magma?
>> >> > Someone was able to test version 1.2a1 in Pharo 1.1.1?
>> >> > Thanks in advance,
>> >> > Facu
>> >> >
>> >> > _______________________________________________
>> >> > Magma mailing list
>> >> > Magma@lists.squeakfoundation.org
>> >> > http://lists.squeakfoundation.org/mailman/listinfo/magma
>> >> >
>> >> >
>> >
>> >
>
>