Originally Posted by torpedobait

Be sure that all folders, sub-folders, and files are not set to Read Only. Right click on the base folder where you installed the game (i.e. Silent_Hunter_IV or whatever you called it). Select properties, UNCHECK the Read Only box, then CHECK the "Subfolders and Files" box. Click on Apply. It will take a few minutes to complete the process. That should allow JSGME to apply the mod properly. Worked for me, anyway. Good Luck.