Wifi tethering - Mighty Mike's

I'm assuming it's using the HTC WiFi internet sharing (aka CM XDA blah blah whatever).

Disable wifi alltogether. Soft reset your phone, start up the app again and have it start. Wait till your wifi icon has been doing the connecting animation for about 10 seconds - then go try to connect to the peer-to-peer network on another device.

That may also be another issue, the network is peer-to-peer (aka ad hoc) and some wifi software filters out ad hoc networks by default. I know my sister's iPT had to be set to show ad hoc networks before she could connect to the hotspot from my phone.

Be mindful to stop the connection on the device instead of just turning off wifi. After it's stopped and wifi turned itself off again, try connecting to a legit wifi network with your phone and disable the cell radio - try to load a page. If it doesn't load, your wifi has issues and you should try a hard reset, anyway.

Just a few guesses to try.