Toyota Repair: 89 Supra with Targa top leaking water, rtv sealant, drain tubes

Question
I have an '89 Toyota Supra with a targa top that leaks water near both channels (driver and passenger sides) to the interior after rain.  Somehow water is collecting in the channels but I can't seem to figure it out.  I fixed it temporarily by placing some black RTV sealant in the channels of the targa in places I thought to be the cause of the leaks.  The leaks have now returned though.  Is there anything specific you know about repairing this problem?
Are the channels on the body of the car the problem, maybe?  The water also gets to the headliner and soaks it on each side around the areas where the targa joins the rest of the car (front and back).
Thank you.  

Answer
Check the drain tubes, one or more is probably clogged and won't allow the water that collects in the channel to drain out the bottom, you can see the drain tube openings on both corners of the roof opening, you can try to clean any obstructions with a long flexible, stiff wire, another possibility is that one of the plastic tubes has come off inside the "A" pillar, these are the pillars closest to the windshield, remove both plastic covers and check to see if the plastic tubing is attached to the metal pipes, you may have to pull the corners of the headliner down to check for this.
The first step should be to check for a clog, do this by opening the roof and with a bottle filled with water pour some into the drain channel and see if the water exits at the bottom of the car, if it collects and does not drain one or both of the tubes is clogged and will need to be cleaned out.