MacOS – Network Link Conditioner not working

I am a web developer and I recently found out about Network Link Conditioner, but I can't get it to work.

It appears to be working, but when I load anything in a browser, the speed is not changed, regardless of whether or not I use 100% packet loss, etc.

Can anyone tell from this log what might be causing this?

OS 10.7.5, Xcode 4.4.1.

I have tried uninstalling and rebooting in various sequences but no improvement.

Also did the steps here:
https://stackoverflow.com/questions/12414676/network-link-conditioner-seems-to-have-no-effect-on-network-behavior-on-lion-mo

When I switch it on or off, I get this in the Console:

1/19/13 3:28:19.142 PM [0x0-0x38038].com.apple.systempreferences: System Preferences(683,0x10e0b1000) malloc: *** auto malloc[683]: error: GC operation on unregistered thread. Thread registered implicitly. Break on auto_zone_thread_registration_error() to debug.
1/19/13 3:28:19.533 PM NLCd: API Version mismatch
1/19/13 3:28:19.534 PM com.apple.nlcd: Jan 19 15:28:19 Jason.local NLCd[698] <Notice>: API Version mismatch
1/19/13 3:28:19.534 PM [0x0-0x38038].com.apple.systempreferences: _nlc_stop_simulation: (os/kern) failure
1/19/13 3:28:19.534 PM System Preferences: process command (simulate) failed
1/19/13 3:28:19.536 PM System Preferences: Stopping Network Link Conditioner
1/19/13 3:28:19.537 PM NLCBackgroundApp: Received callback that simulator was stopped!
1/19/13 3:28:31.408 PM [0x0-0x38038].com.apple.systempreferences: _nlc_start_simulation: (os/kern) failure
1/19/13 3:28:31.409 PM System Preferences: process command (simulate) failed
1/19/13 3:28:31.441 PM System Preferences: Starting Network Link Conditioner
1/19/13 3:28:37.105 PM _securityagent: audit warning: allsoft
1/19/13 3:28:37.105 PM _securityagent: audit warning: soft /var/audit
1/19/13 3:28:37.106 PM _securityagent: audit warning: closefile /var/audit/20130119222807.20130119222837
1/19/13 3:29:07.100 PM _securityagent: audit warning: allsoft
1/19/13 3:29:07.100 PM _securityagent: audit warning: soft /var/audit
1/19/13 3:29:07.100 PM _securityagent: audit warning: closefile /var/audit/20130119222837.20130119222907
1/19/13 3:29:37.104 PM _securityagent: audit warning: allsoft
1/19/13 3:29:37.104 PM _securityagent: audit warning: soft /var/audit
1/19/13 3:29:37.105 PM _securityagent: audit warning: closefile /var/audit/20130119222907.20130119222937
1/19/13 3:30:07.103 PM _securityagent: audit warning: allsoft
1/19/13 3:30:07.103 PM _securityagent: audit warning: soft /var/audit
1/19/13 3:30:07.103 PM _securityagent: audit warning: closefile /var/audit/20130119222937.20130119223007