when you are configuring the virtual sever settings, make sure the port number, IP address, especially the Use Interface are correct. otherwise, you may do a DMZ for the camera's IP.

Probably you can delete a profile on the computer and reconnect the wireless to see whether it will work or not. for windows XP: http://www.tp-link.com/en/article/?faqid=186 for windows 7 and vista:...

As far as I am concerned, the 5GHz device cannot discover another device from 2.4GHz, if you have a 5GHz router, this adapter cannot be connected through 5GHz.

I tried the link you gave here, and it is working... Maybe you can try this one: http://www.tp-link.com/en/support/download/?model=TL-WR740N&version=V4#tbl_j

It seems no much difference between the two adapters, and there is no information on the web site. I guess maybe the compatibility has a little difference:)

there is no such a model on their website, I guess they do not have a English version for this.