Hi,
You don't say what kind of adapter you bought. The PCMCIA on the A1200 has a major problem with the reset command. You might have to buy the PCMCIA fix from Amigakit (
http://www.amigakit.com) called the Amiga 1200 pcmcia cc_reset fix. The next thing you might want to buy is the Easy ADF, this gives you the software set up for the Amiga 1200 to transfer files.
Now if you bought an pcmcia cf card adapter for a pc laptop, I have bad news it probably won't work because of the lack of software, I may be wrong. Hopefully one of these fine other Amiga loonies that hang out here will be able to help you.
But by buying the two things I mentioned above I know that works because I use them.
smerf