96 Accord range? issues

Hello guys.  I have this awful problem with an Airwolf 20096 that I installed on my 1996 Honda Accord.  It seems to be a range issue.  The only way that the 2-way remote works is if I'm standing within 10 feet of the car, and even sometimes then it won't work.  The car usually receives the signal from the remote, but the remote doesn't always receive the signal back from the car.  A lot of times I will get the "HOPP" error, meaning that it couldn't get the right code (it's a code hopping system), and I have to try again.  I tried relocating the antenna so that it wasn't under the window tint, I relocated the ground wire to a wire under the hood that connects directly to the negative battery cable, and none of those fixed the problem.  I have the same system installed on my other vehicle, so I started swapping components, including the brain, antenna, and remote, but that didn't work either.  When I put the components from the Accord in my other vehicle, it worked fine.  This is driving me nuts.  My wife refuses to drive the car at night because sometimes she can't get the car unlocked until she's right up next to the car, and even then sometimes you have to press the button a couple of times for it to work.  I just have no idea on what to check next.  This car doesn't have an external antenna for the car radio, I'm assuming it has some kind of internal antenna.  Could this be interferring with my r/s system?  If so, how can I fix it?  I'm half tempted to buy the range extender that DEI sells for this system, but I don't know if that will fix my problem either.  Please help.  I'm selling this car next year, and if I can't get the bugs worked out, I'll have to remove it.

What kind of wiindow film/tint is on the car and what windows are tinted?  Some films are metalized and if your have all your windows tinted it will screw up the range.

I moved the antenna so that it is below the window tint.  That didn't solve the problem either.

No, there is no other tint on the car.

That doesn't seem to work real well either.  Velocity Motors told me to try and relocate the antenna again, so as soon as I get a chance, I will try that.  Has anyone had any problems like this on this car before (1996 Honda Accord)?