Update Error JEM 4.1

I tried to update JEM to 4.1 and I got this error :
JInstaller: :Install: erreur SQL Duplicate column name 'requestanswer'
What is the problem ?

Hi, this is known
you just tested with JEM 4.0.1dev.
Because the 4.1 is for upgrading from 4.0.0,
During the first try to update, you get an error.
Then go in Joomla System Dashboard to Maintenance>Database, repare Database JEM.
Then install JEM 4.1 again. No problems!

Thank you
t's OK now
I should have actually checked the status of the JEM database in Maintenance / databases and repare the problem.