Cannot put decimal prices

[brian!]

then from the outside, I can't think of what else to suggest.

if your license owner had a dev license, it might be worth creating a clean test install - e.g no custom templates/hooks/addons, just using six & sc with a clean empty database, and see if the error reoccurs there.

[Arnaud Lier]

@ZeProf2Coding The problem was that I have 

setlocale(LC_ALL, 'fr_FR@euro', 'fr_FR', 'fra_fra');

in  my configuration.php file.

[brian!]

thanks for the update - i'm glad that you managed to figure it out. 🙂