Sd Mmc Reader SD/MMC Card Reader Through Usb ?

SD/MMC Card reader through usb ? - sd mmc reader

I tried my SD / MMC removable drive on my PC to connect using a USB extension cable, but when I go to my computer> d :>... I get the message: Please insert a disk into drive D:.

That is, they can not access the SD / MMC to transfer photos to my PC.

Occur in my old PC, only the card reader in order to invite a folder to open my pictures, why now, when I this problem?

The only good thing, if I connect the card reader connected directly into my USB port I can access files on my computer.
And to complicate matters further - the extension cable hub works with other USB devices?