I think i have found a bug in the new version, i did a clean install, and at the end of my install a batch file calls a reboot (with shutdown.exe), but at this time instead of closing wpi has shown a message that said that there was a error in generate.js at the line 16 (if i good remember) in the SetScriptWaitTimeout function.

I think i have perhaps found where the problem comes from, in a bacth file i detelte the following key : hkcu\software\microsoft\internet explorer\styles before wpi ends. It think it could cause the problem.

That's correct, because when you exit WPI after clicking begin install it deletes that key, and since it isn't there to delete it is failing. Perhaps some code can be added so if that key doesn't exist then it should just continue (perhaps this is the desired behavior but it's just broken).