For those stuck try this find a website with adverts on copy the address (Example www,example,com/not_real.html) open the trainer and press Ctrl and O paste the address in the boix given and press enter. Let the page load and either right click open in new window or just normal left clicks work.
Here is a step by step guide.
1: Open LGz Trainer GCNA and wait for it to load.
2: Press Ctrl and O to bring up a pop-up and enter Perucheats.com (Image example is using a different URL but I have tested with this site too)
3: Right click on the advert you can bearly see and select the option "Open in new window" (If right click is unavailable then normal left clicking would work)
4: THis has made your click count "1" Repeat step 2 and 3 and you will be able to open the trainer.
5: Click "Open Trainer" and start the game-up, login game and pick what options you want to use in the world map (And only in the world map can you activate/disable cheats). And ejoy the game.