Why do you hide the link in an mathcad sheet and there in a png-file?
BTW - the link is not quite correct, you linked to the kalkulator but meant
http://www.wrotniak.net/works/testfpuThe good news are, that the FPU is not blown up or destroyed but that the author is talking about some particular background processes are able to affect the precision of the FPU outcome. The article and software mentioned are rather old, so it possible won't be a problem in 2010.
Concernig the 10^30 effect I would rather stick to Toms explanation.
According to floating point rounding and converting errors its also interesting and well known, that computer math does not follow the commutative law for summation for the reason of the set of numbers not being infinite. E.g. the order in which the sum of 1/k with k running from 1 to an arbitrary integer N>1 is evaluated affects the result. See accompanied sheet, if you are interrested.
Regards
RMix