Hello everyone , I've downloaded the full firestorm game second time (this has no bounds with the solution ) , and I've started to try doin things about the CAS error .
Ok so what made it work ?
Step 1 : Download the full game from with Firestorm's torrent
Step 2: Delete/Uninstall Firestorm launcher
Step 3: Reinstall Firestorm launcher
Step 4 : Run Firestorm launcher , select the option Already Installed ? from wod section, Select directory of ur full game , let it do the stuff it has to do
Step 5 : Open wow folder , delete WTF folder , then delete WoW.mfil , then move to the Interface and download the ADDons follder.
Step 6 : Go to the place you have your wow folder ( you must select your wow folder in this step , like the folder that contains everything ) , right click on WOW folder , unceck read only for the enire folder hit OK
Step 7 : Play and send gold to Gcdhacker on Grommash
P.S: hope it works for you It did worked for me HF