Arturo,
After you download USB Adapter Card Support 1.4.1 here...
http://docs.info.apple.com/article.html?artnum=31132
...also download TomeViewer here:
http://www.versiontracker.com/dyn/moreinfo/macos/4561
The installer in USB Adapter Card Support will not install on the 3400; TomeViewer will put the USB extensions on the desktop from the installer.
Once you have used Stuffit Expander on the USB
Card_Support1.4.1.smi.bin download, mount the (.smi) file on the desktop. Launch TomeViewer...there will be no window, work from the menu bar...go to File > Open > find the USB Adapter Card Support installer > open the USB Adapter Card Tome. A window will open listing the seven USB extensions; highlight one > go to the menu bar > Archive > Expand > a window will open with the name of the file to be expanded > select 'desktop' at the top of the window > click 'expand' > do the same for all seven extensions.
Now quit all applications and utilities > open the HD icon > drag-copy all seven USB extensions on top of the closed System Folder icon > you will be prompted and they will automatically be installed in the Extensions folder. Now just restart and see if the USB PC card will work.