Linksys router question

[s37d]

I have a Linkysys BEFSX41(wired router), and I'm trying to block certain sites from being accessed on a networked computer. I've tried putting in keywords as well as the url of the site, but still it can be accessed. I've tried putting in MAC address for the pc, as well as the IP of the pc. I've even checked "All PCs", but it still wouldn't block the site, not even on my computer. Not sure what I'm missing here, any help would be appreciated, thanks.
Here's a pic of what it looks like:

 

[kfc469]

see where it says deny? you have it set to allow. change it to deny and I think that that will fix it. your router is slightly different than mine, but you have to choose deny on mine to make it block them

 

[s37d]

When I click deny, it grays out those 2 boxes(Website blocking by URL address and Website blocking by Keyword), which typically means that it's not going to do anything. I tried it anyway, but it didn't work.