Battlechest problem....

So i wanted a second account so I went out and bought a second copy of wow which was a battle chest of original and burning crusade then a copy of wrath. I started making a new account and not being familiar with battle.net I end up making a free trial account which was no big deal. The big deal is when I actually made the account I wanted under my main battle.net account I accidently put the CD key on that dang free trial instead of my account. So the trial account was upgraded to full. Still my mistake so I gave a big /sigh then went back to the store and bought just a single original wow copy. I installed that into the proper account and start playing with my free month time.

So here we are now, my shaman just got level 58 and I started to try and install the Burning Crusade that came with the battle chest and it wont let me, which i'm assuuuuummminnnnggg that it has to be installed in conjunction with the battle chest original copy and wont work as a stand alone copy of BC.

This made me very angry, the first time was my bad and i spent another 20 bucks but I dont think it's right that now i have to go spend another THIRTY bucks to buy another copy of BC. Infact unless a very nice GM helps me I will just cancel it.

I spent my money, its says nowhere on the box that its not a stand alone copy and has to be used with the original wow copy in the box. So am I screwed or what?