well you MAY have answered your own question considering the IRman plugin
Have you tried running the system for a while with out winamp up? Have you tried uninstalling the plugins?
It's entirely possibly your memory has gone sour.. or some other bit of hardware.
I would try disabling some plugins and if that doesn't do it see how well the system runs under burdens other than winamp.. if it's still crashing you've probably got a dodgy cpu or memory. If it clears up the answer should be obvious.