Image Card reader (ImageMate 12 in 1)

My ImageMate 12 in 1 card reader displays the drives on my computer.  When I place a card in the adapter, it lights green, but when I click on that particular drive it says insert card, what can be the problem.  MY O/S is Windows Vista 32 bit.

either a bad card or reader. does the card work in other hosts? do other cards work in the reader?