The bugsfreq file you presented here is corrupt
of course that means corrupt in computer-terms :) :)
meaning that it contains some errors or it is formatted wrong
Someone told me it is also available from cryptome
so i downloaded it from there..and that one works fine
no need to insert or alter any kind of serial-numbers
just open it in CS-R20 and voila.
I now have a copy of it available from my website
along with some other small programs that let you
sort and work with Icom icf-files