It sounds more like the wireless network adapter in the laptop isn't disconnecting properly from the access point when it's put into hibernation - as far as the router's concerned, the device is still connected, and you can't connect to something if you're already connected to it.

Check for more recent network adapter drivers from the manufacturer's website and install them.

There may be an issue with the router/access point, so you could try upgrading the firmware on that if there is any more recent firmware available.

Check the settings for the network adapter in the advanced tab after you click configure, when you get properties on the network connection. Check there's nothing about 'power saving' enabled.

Wireless encryption is a pain in the doodah (especially if you don't use copy and paste ), but as long as you can use the same encryption and keys on both devices, you'll never have a problem. Encrypted wireless networks normally have a more reliable, if slightly slower, connection.

If you can, connect to the router with a cable, and have a look in the connected devices page (or whatever your router calls it). If your wireless device's MAC is still there, it's not disconnected properly, though this is normally countered, thanks to a timeout.