Windows unable to find certificate to log onto wireless network

[Elliah]

i've just set up a wireless network at my place. there's 5 of us using the wifi network. so far i've gotten 4 of the laptops connected, up and running. The original computer i used to set up the network keeps showing the above error message. This message showed up in the other computers as well due to a problem with the WEP password, which has been resolved.
I have tried setting the configuration to open as well as shared but this message still keeps popping up and it cannot connect to the internet via wireless (although it works perfectly by cable) any help?
the laptop is an acer aspire 5572nwxci model running on windows xp. the router used is a dlink dir-615 wireless n router.

 

[rf6647]

If this remains unresolved, here is the bump. If solved by you, share your solution with others.

Having 4 other laptops to inspect for differences in the wireless configuration properties, you may have stumbled upon an obscure setting.

The router may impose limits on the number of wireless clients connected.

 

[Didou]

Did you set a limit on the amount of wireless connections that the router should accept ?

 

[Elliah]

ok..solved it...it worked after i turned off 802.11x authentication...thanks for the advice