What happens if you connect a standard USB flash drive to the phone? Can the phone detect that or do you get the same issue?
Not all flash drives and card readers will work. Some card readers may for example require specific drivers or require more power than what the phone can supply.
Then i'm afraid it sounds like the card reader you have is not compatible with the phone.
If possible, try connecting the SD card with another card reader. Also note that connecting more than one external storage at the same time may not work.
