Did you try the other fixes (deleting prefs etc)?
If you've had your antispyware running for a while without it causing a prob for LW, it might not be that.??? Have you updated/upgraded the protection recently?
Somewhere there should be the option to allow certain progs/apps to run regardless of whether the antispyware thingy sees them as a threat. You might just have to have a look (I'm not going to be much help there as I only use Spybot & Ad-Aware)