Hi jewel,
Thanks for the suggestion. I've been using YSmenu for all the roms. Guess will just have to wait for them to update it. I've already reported the issue. I've tried Wood R4 before, but well, let's just say it didn't worked out well for me. Haha!
Firstly, I would "chkdsk /f" the card, then try loading another large game and see if it runs. If both still fail, you may need to reformat the SD card with the Panasonic SD format tool, or another similar app.