autopsy email parser error

Dear friends,

the problem is as follow

1. when I tried email parsing a pst file I got error "java.lang.nullpointerexception error" in the bottom right hand status bar. (image attached below)
2. these pst already been tested with readpst/libpst and libpst can read it.
3. autopsy version used is 3.1.3
4. the 3.1.2 version show no error, but the parser is also not running, so I think it's just something wrong with the error handling.
5. run in win 7 64 bit.

if anyone could help me or something needed to be done for further diagnostic, please do tell me.

thank you in advance.