Wizard accelerometer calibration cannot be corrected after fail

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Run the wizard
2. Fail at step 5 of 16 (or complete)
3. Try to do the calibration again by going back or forward
4. The 'Start' and 'Continue' buttons will never be enabled again.

What is the expected output? What do you see instead?
It should be possible to redo this calibration step

What version of the product are you using? On what operating system?
MP 1.2.92

Please provide any additional information below.
Another error is when one closes the wizard and run it again (when already 
connected) after a failed calibration, an error pops up saying that the port is 
busy.

Original issue reported on code.google.com by huj56...@gmail.com on 10 Jan 2014 at 8:32

[GoogleCodeExporter]

I'm having this issue now  I can get to that point installed all the updates on 
mission planner an on my APM 2.6 get to that screen to set up accelerator an I 
can't do anything. Have u come up with any solutions. 

Original comment by schnecky...@gmail.com on 28 Apr 2015 at 2:14