As NJStar WP is a word-processor, capable of reading variety of Japanese JIS files, it is likely that all the Japanese messages you receive can be read correctly with NJStar provided that "escape sequence" of the original format is not lost.

If you suspect that this is the cause for corrupted data, then try first to save the message to a disk within your Email program, then read the file from NJStar Japanese WP.

A separate program, NJStar Communicator, will allow you to read any Japanese messages directly in your email client without coping the message to NJStar WP.