Well, I already researched in maemo.org, but no managed to solve the problem.

I’m having a complicated problem of connection even before of firmware update.
I can to access voip, skype, email, browser, some repositories...
But never to have access services as the official repositories Nokia, Ovi, MaStory (wordpress) and Webtext (SMS voip).
My firmware is 2.2009.51-1.002, updated via NSU (USB cable), because the N900 could not connect via wifi or GPRS (time out).

Others informations:
I am in Brazil and my GSM carrier is the Brasil Telecom GSM.
GPRS access only if there is no wifi access.
The wifi is in my home with the following configuration: WLAN, WPA, IP and DNS automatic.
(I tried with OpenDNS and Google but without success)
My modem / router / wifi is a TP-Link TD-W8960N and appears to be working correctly.
The modem setup wifi is configured with password (tested without password too).

After the firmware update, all apps were deleted. Currently I have the following softwares installed. (MaStory, PyGTKEditor, Pidgin, pySafe, WebTexter, Cellular Modem Control buttons, Conversations Inbox desktop widget, Link-local XMPP protocol plugin for Conversations and Contacts, MSN protocol plugin for Contacts and Conversations, Pidgin protocols for Conversations and Contacts, recaller, Simple Brightess Applet, Twitter plugin for Contacts and Conversations, rootsh)
After I just installed the apps listed above, one by one.

Suggestions on how to fix it? Thank you!