SipToSis is a program with a batch file that runs java.exe directly with various parameters.
Alas, those parameters aren't accepted by jPortable's java.exe.
Instead of accepting the parameters, jPortable's java.exe treats it as if you tried to run "java.exe /?".
Why is this? Please test SipToSis (it's free) with jPortable. Thanks!
The copy of Java included is completely unaltered. It's extracted directly from the official Java installer as you install jPortable.
Sometimes, the impossible can become possible, if you're awesome!
SipToSis is free and portable so you can easily test it yourself.
Maybe you'll figure out what's wrong.