well, there sure are lots of chatters in IRC and you can't expect them all to behave as you wanted them to...
if a chatter is like threatening you with things like that, dont forget to use the /ignore nick so that you won't be troubled seeing what he's saying. with regards to those malicious files, trojans, viruses, etc. he's saying that he would send you, well, just keep in mind not to permit or say Yes to DCC sends that came from those persons you don't know or trust. yup, downloading some firewall could also help.
well, i guess your PC will be A-ok by just bearing those basic reminders in mind...