You are receiving this error message because your computer believes that your MiFi is a 802.1x access point. By default the MiFi is not configured to use that protocol so we should look at configuring your PC.
To change the wireless security type on Win7r:
1.Open the Network Sharing and Sharing Center
2. Click Manage Wireless Networks
3. Highlight and Right Click the wireless profile for your MiFi
4. Select Properties
5. Click the Security tab
6. Change the Security Type to WPA2-Personal
7. Haz clic en OK
8. Test the connection
Post back and let us know if this resolved the problem or not.