We have also had this problem. We used the iPad on our recent trip to Fiji and to be honest it was unusable for viewing never mind deleting or editing images.
Roddy installed Cool Iris which allowed us to view them ok but it can not do any more than that.
It also looks like we have lost images from the iPad, it appears that the iPad has dumped the RAW files if they have been accessed in anyway. The images that Roddy had looked at with a program called photogene appear to have autosaved as jpg and dumped the RAW files.
He is not amused. Sorry we haven't been able to help but we share your pain. Also be careful which work-a-round you use - you may end up regretting it.
Sharon & Roddy