Actually Opera does XP very well, it just doesn't update itself (what is actually good), even not at my request (what is bad).
I installed new Opera into another folder, fresh opera_autoupdate.exe produced same kernel error (and because this error is likely be thrown by windows before even running the code, then uninstalling won't help). Apparently they (Opera team) have either decided to break XP compatiblilty or did break it accidentally. Searching google shows similar errors with many applications, including some versions of Chrome Canary autoupdates (which were promptly fixed).