It sounds like you've done everything right, although the best way to move your settings over is to use the Backup / Restore feature built into FlashFXP. If you still have access to your original installation I would recommend you do that. click
here for more info.
Since you tried copying the files over it may have messed up the ACL or file permissions but its really hard to say for sure.
You can verify the location of your FlashFXP data folder from within FlashFXP, from the main menu, Help > About, and then click on the Details tab.
Re-installing FlashFXP may not be able to resolve the issue if there's a permission problem with the data file.
Threaded Mode