You can try to copy the save folder from your old game files (/www) and paste it to the new www folder. There's a chance it won't work. There are also preset saves in the game you can use so you don't have to start from the beginning.
Do you still have save files from before you pick up the purple fruit on Pine Island? That might help. Otherwise, try re-downloading the game, and use the prepackaged save files. Save 03 puts you right on Pine Island just before you're about to leave with the purple fruit in your inventory, and I promise you won't be losing any items, solved quests, unlocked scenes, or be underleveled using those files. You only need to remember to switch your equipment, spend all your free stat points, and maybe visit the ID machine in the Gloom Forest to change the Adventurer's name back to what you were using.