How about reset them by using the CD software utility and then give a try. If still the problem, i think you can try to disable the power save function by this tool:...

There are no setting required when you turned them back on because they are just plug and play units. But i heard that, it is not good to unplug them from wall sockets every day but can unplug them...

Here is the instruction on how to make TP-LINK work as an AP: http://www.tp-link.com/en/article/?faqid=417

The firmware you got is released on Feb 9th 2012.

On the TP-LINK website, there is a tool that can disable the power save function.Here is the download link: http://www.tp-link.com/en/support/download/?model=TL-PA511&version=V1#tbl_b I think all the...

Are you using a cable modem or using a DSL modem? How about disable the Hardware nat to give a try?1