As always, when messing around with stuff in root/recovery, make sure you're backed up.
One thing that I've had to do is completely remove the config file (or files in your case); make sure you save them on your computer or somewhere where you can put them back if needed. Also, make sure you just remove the carrierconfig files and nothing else in that directory.
After that, boot up into Android and make sure that all SIMs are working as expected (reception, data, text, etc.) and that they have the correct APN set in settings. Then try going back and modifying the files; Android should re-create them.