Check if wireless extensions are compiled into kernel:

tux@slitaz: zcat /proc/config.gz | grep CONFIG_WIRELESS_EXT

CONFIG_WIRELESS_EXT=Y

Thank you for the reply Mojo and you excuse for not answering before.

The new kernel doesn't include to the wireless extensions for default and so that he makes it is necessary to activate the option:
"Enable mac80211 mesh networking (pre-802.11s) support"

and also to include the module:

"Intel PRO/Wireless 2100 Network Connection."

Fact this the kernel this way built if it includes wireless extensions and ndiswrapper now it is compiled and it works without problems.

However I have found other problems because of the upgrade of the kernel 2.26.33-4:

1) the module of Virtalbox neither works; solution but it cleans: to upgrade Virtualbox to the version 3.2.
2) Dazukofs fails when being compiled against this kernel and this time the upgrade of the version 3.1.2 to the version 3.1.3-rc2, it solves the matter.
3) Another problem is to make work the Realtek r8185b propietary driver; that it compiles and it loads, but it doesn't work and to which I have not found upgrade neither solution.
4) To finish the module of hardware monitor W83627HF that comes included in the sources of the kernel and that before it worked without problems, now it is built but neither it works.

Due to these regressions that diminish the functionality of my computer, I have decided to return my PC to the previous kernel and to await until all these incovenients has been overcome.