i think since very few have reported such a crash and you seem to have sp3 in common with 'very confused', then this crash is more than likely related to sp3 than kmeleon itself.
remeber when sp3 was first out, it was a mess and in a way still is with certain hardware.. back then, ms listed on their site the incompatibilities. sp3 crippled hp printer drivers, crippled ati based graphics drivers and completely rendered amd athlon cpu computers useless. if you ask me..this sounded more like a virus than a true update. it made your expensive graphics card no much better than a savage 3d 8bit using the generic xp driver, your hp printers unusable and if you had an amd pc..then bye bye.
later some of these issues were remedied, some by ms themselves like fixing amd problems..some by the manufacturers like hp offering driver updates that work with sp3..and some partially fixed like with ati drivers, where the driver will work but the ati programs cataylst or hydradm becoming only half functional.. so it's still a botched updated even if it only affects certain hardware and works fine with other configurations.
this is from personal experience: couple of months ago i was at a friend who uses kmeleon and there was something very strange about it..it felt slow with certain jerkiness when selecting menus or clicking buttons..it almost felt like firefox
when i asked him what was wrong with his pc(a quite capable dual p4 and actual dual cpu;s not dualcore or other virtual nonsense).. he proudly confessed that this happened right after he installed sp3.. a must he sez to keep the system updated with the latest patches.. well, that;s actually not so true since you can download all the xp security updates and fixes separately and you'll pretty much have your own version of sp3 without the other rubbish that causes problems. and this is what he did, i showed him the links to get all the needed updates..he uninstalled sp3 and applied the patches separately and his system was as good as new.. honestly his km didn't crash but it didn't work quite right with sp3(along with other net-related programs)
try to do this..first, for rest assurance; make a restore point for your current system then remove sp3..reboot your computer and test km for couple of days..if it doesn't crash then you have pinpointed the problem..keep your system with sp2 and download all the security updates and patches that come with sp3 separetly from ms site..they are all available for free without charge.