Epson stylus photo 830U, black cartridge installation pb

Hi,

A few days ago, I had to change the black cartridge of my printer (model of the cartridge T026).
Once installed, the error message 'black ink cartridge not correctly installed' appeared. I thought it was a problem with the cartridge itself so I went to buy a new one, same problem. I uninstalled the driver and all the software linked to the printer, re-installed the whole mess, same issue. Now I know the printer works just fine and that the cartridge is the correct one (I've been using the same model for over a year).

Any suggestions. Any help would be appreciated.

Oh, and hi to everyone, being new here and all. Thanks to the moderators, administrators etc for such a great forum.
Sorry for my English.