I was looking around at curse and happened on this lil bit of info... I am using questfu and it is what was causing this problem.
guido666 said
Thursday, October 30, 2008 2:45:25 AM (last month)
I just figured out that this addon was causing my alerts (e.g. "You can't loot that yet.", "Requires 375 mining.") to not show up. Going under the menu to Modules > Player Status, and UNCHECKING it, makes it work again. I'm not sure of the cause.
Tried it out and sure enough error messages came back
just figured I'd pass this along in case someone needs the info.