It is quite known that ORIHIME's own file format (*.orh) files could have encoding issues in various environment, yet I'm not aware of an existing solution. After some experiment I came up with the following command to start ORIHIME that can solve the problem:
java -Dfile.encoding=utf-8 -jar [path/filename of your orihime.jar or orihimeMod.jar]

As can be seen in the first picture, for the original ORIHIME (not the mod), the output file is then perfectly encoded. However, things are not exactly so for OrihimeMod, as can be seen in the second picture.

This doesn't stop the file from reopening though, as long as the file is also output by OrihimeMod itself. But, even when running under UTF-8 mode, Orihime and OrihimeMode cannot open files saved by the other. I guess something didn't go quite right when you compile OrihimeMod, see if you could investigate into this.