I believe if you lift up the seat bottom of the back seat you will find a ring and cable pull to release the boot latch from inside. Then check to see that the latch is open and moves freely before closing the boot again. Should get you back in business. Good luck!
--What happens when you hit the boot release button on your key? Do the lights flash? If it does and your boot still won't open there is a manual release latch behind or under the rear seats but I believe you have to drop the rear seats to get to it. Check your drivers manual, it will tell you how to manually open the rear boot. If the lights don't flash then you might have a key problem. Try your spare key.
Here is what one other NAMer said: There is a "pull ring" tucked under the rear seat to open the boot if there is an electrical failure.
Thanks for replying so quickly. When I use the key the lights blink, but I cannot open. I'm reading through the owern's manual right now. Hopefully, I can find the release shortly here. I'll let you all know if it works.