Freezing, can't force quit.
 

This has been happening with 5.5.4 and the latest 5.5.3 builds. I'll be running Omniweb, everything's fine - and maybe I try to open a new tab, or close an existing one (there's really no consistency with this problem). Anyway, OW locks up. So, I try force quitting it from the Dock - and when I check in Activity Monitor, there's nary a trace of Omniweb. But the icon's still in the dock - with the little running indicator next to it. I could try force quitting it or killing it numerous times, but according to OS X and the terminal, it's not running. Eventually my entire system grinds to a halt and I have to shut it down manually - since it takes forever to interact with menus. I'm pretty stumped here and any advice would be great.
[B]System: [/B]
MacBook Pro 17" 2x2.16
1 GB RAM
[B]APEs installed:[/B]
ClearDock
IceCoffEE
Instant Hijack Server
[B]Plugins:[/B]
A float, JavaPluginCocoa,megazoomer,flash player,flip4mac wmv,iphotophotocast,quicktime,verified downloadplugin, quart composer

Anything other info that'd be helpful in diagnosing what's going on here?

Hmm, strange.

One thing: If both "ps ax" in the Terminal and Activity Monitor say OW isn't running, it isn't running. So there must be sth wrong with the Dock (or some stuff that changes the behaviour of the system) rather than with OW.

I don't if that's exceptionally helpful, but at least you know where to look.