If you have an original Super Smash Bros. Brawl disc, try loading that and see if that works. If it doesn't, or at least sometimes gives you some disc read errors or something, then you may just have a dirty lens and can try using
THIS to fix the problem.
Edit: Other possibilities: If you are on a system menu thats higher than 3.2, then directly installing a cIOS would not have worked. Are you sure they installed successfully and didn't give some error at the end before going back to the HBC?
If that is the case then you have to run the Trucha Bug Restorer first and have it downgrade IOS15 first, then run it again using IOS15 and then go to the IOS36 menu and install an IOS36 with the trucha bug and ES_Identify, and then run it again from IOS36 and restore IOS15.
Then run the cIOS rev14 installer and have that use IOS36 when it prompts for it and then do a network installation or wad installation after getting the IOS38 wad if you dont have wifi..
Also, don't burn at 2x, a good speed is half of the maximum speed the dvd supports.
If none of those work, you may want to try different media for your discs like normal DVD-R's