Let's address the central issue:
: OpenCPN natively supports CM93 v2. To use them, you must point the software to the top-level directory containing the .EXD version file and the 144 geographical subdirectories .
Assuming you have acquired a legitimate (or legacy) copy of the CM93 v2 folder, here is the standard installation process for (the most common compatible software):
Computer Science, Information & General Works 
Philosophy & Psychology 
Religion 
Social Sciences 
Language 
Pure Science 
Applied Sciences 
Art & Recreation 
Literature 
History & Geography