There is micro switch is located in the luggage compartment (trunk), what it does is prevent the convertible top
from being opened if the shelf in the truck is in the raised position. If the shelf is in the raised position it allows more room in the trunk.
To start with look inside the truck towards the top on both sides of the shelf and you will notice trunk knobs and they almost look like gas burner knobs on an outdoor gas grill, when you turn the knobs one direction the shelf will raise when you turn them the other direction the shelf will lower. Make sure the shelf is in the lowest position and try it again, if that doesn't correct it put the shelf in the raised position and look under the shelf towards the front of the car (where your seat backs would be if you could see them) and you should see the micro switch, how it works is that there is a little tab on the shelf and when you lower the shelf it is supposed to make contact with the switch which tells the system the shelf is lowered and the top can now be opened.
Let me know if that doesn't correct the problem.
When you press the open button does your windows lower half way and the top release from the windshield? If so, you will be able to see it raise about a 1/4" from the windshield (un-seal from the windshield) and when you push up in the center of the top (at the winshield) it will move away from the windshield.
There is also the hyd. release valve that is located in the truck
as well and if it was pulled and turned 90 degrees by mistake (little red handle in the upper left hand corner of the truck if you are facing into the truck) it will prevent the hyd. pump from working, however the windows will still lower and it will release from the windshield.