I can't load DWCS3 software onto my Mac, claims itsalready installed.

I had the trial version of Dreamweaver CS3 on my computer until it expired. I
bought the software (Adobe creative suite 3 web premium). I tried entering the
serial into the trial from the suite and it didn't work. Mind you I installed
successfully all the other programs (Illustrator, InDesign...etc.) and they
work perfectly. When I installed everything else it said Dreamweaver was
already on my computer. OK...fine... delete trial version and reinstall the
software. Still nothing it keeps saying its already on my computer.

Does anyone know how to fix this!??!?!?! I bought the software and have it
sitting RIGHT in front of me and still can't use the ONE program I really need.