I have the kryptonite version with integrated lock.  It has one of the highest security ratings and I purchased the "full replacement" insurance if the lock is broken and the bike stolen.  Send in a photo of the broken lock and the police report, and they fully replace the cost of your ebike. 

Howdy Folks.

Just signed up so I can reply to this.  New RadRover--well, one month old and ~100 miles on her.  I just installed the rear rack a few weeks ago.  I have seen this "Error 25" a few times now, but it is always the same:  I turn on the battery, press the Mode switch for the display, Error 25 flashes on the screen for a few seconds, then it goes away.  If I press the Mode button again, it is fine from then on. 
This is the *only* time I have seen the message.  And it has only happened about 3x now.  It has never stayed on. 
So reading through this thread, it seems it does have something to do with the cable extension from the controller through the cable that comes with the rear rack to the now relocated tail light.  At least in my case. 
It is nerve wracking to see that...because I then worry about something like, what if this came on and stayed on out in the boondocks somewhere?  But hopefully, that never happens.  And this thread has given me some things to try if it ever does.

Ride on!