Hello Oellness,
Here are a few things I would try. I would try each in turn.
1. Ensure that you have Wireshark installed which will mean that winpcap is installed. uTasker uses winpcap to create a bridge to its virtual network. This is probably installed otherwise I think uTasker would not run correctly.
2. When Running the simulator ensure that you go to the menu bar and under the "LAN" option choose "Select working NIC", then using the drop down box choose the network adapter that is on the 192.168.166.xxx subnet. If this shows "No Device used for simulation" or the wrong network adapter, then you will need to stop the simulator and restart it. Because uTasker only checks this value on program startup.
3. Ensure that the Lan adapter that you are connecting to in uTasker (The one on your 192.168.166.xxx subnet), is actually plugged into something and shows a link light, winpcap seems to need this.
4. You may have some firewalls running that block communications, try disabling them.
For simulation work, I have installed the Microsft Loopback adapter and created my own virtual network for testing, you could do this and create a virtual subnet on 192.168.1.xxx for instance and change the uTasker address to be say 192.168.1.166. I use windowsXP and have not tried installing the Loopback adapter in windows7 see
http://support.microsoft.com/default.aspx/kb/839013 for info on installing it in XP. It looks like you can do this in Windows7 too see
http://www.windowsreference.com/windows-7/how-to-install-a-loopback-adapter-in-windows-7/Lastly for simple testing you do not need to set the Gateway and DNS in utasker, this is only needed if uTasker needs to resolve NAMES etc. Its not needed for simple Ping tests.
Good Luck
Martin