Hi J-Rad, I too have been having all sorts of issues as of late with my FTB on my Mac. It was working flawlessly then all of a sudden, it wouldn't work at all. Check to see if your java updated maybe. I had to remove Java 7 then go back to jave 6.
Also, for me to launch I had to creat a folder on my desktop, called FTB, put the launcher in in that folder, change the settings in my launcher to save to that folder and then I have this line of code I put in the terminal and hit enter.
export JAVA_HOME=/System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home
cd ~/Desktop/ftb/
export JAVA_HOME=/System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home
java -jar FTB_Launcher.jar
When I do this, it starts the launcher and allows me to start up DW20 and play.
Look for posts by " Booker the Geek" , he is very knowledgeable and has some great info. In his sig, he has some links to some helpful stuff.
Hope this helps.