The same error? Is there any other computer for you to install the adapter and have a test? Go to Properties of the adapter and check Device Status. What does it show there?
tl-sg1008p can power on PoE IEEE 802.3af compliant PDs. If your cameras are not, you can use tl-sg1008p plus four TL-POE10Rs to power them on. http://www.tp-link.com/en/faq-167.html
Uninstall the driver first. Download the driver for Win 8.1 here and install it. http://www.tp-link.com/en/download/TL-WN722N_V1.html#Driver
Your cameras are 802.3af PoE compliant? The switch is TL-SG1008 instead of TL-SG1008P? But it is TL-SG1008P that has four PoE ports.
Forums/ Wi-Fi Routers
Go to IPv6 Support---IPv6 Setup page. Uncheck Enable IPv6 or change WAN connection type to Tunnel 6to4. If it doesn't help, change MTU on Network---WAN page to 1440 or 1400. BTW, what's the hardware...
Is it what you need? http://www.tp-link.com/en/faq-887.html