Thank you @Mark_R!!!

It would be a great suggestion from implementing a custom naming of the backup file, as it does not support other format of characters (i.e. Unicode). That way QB would not face that issue. Other solution would be to use short date format instead of long date format. That way month would be a number and it would not cause this issue. Other solution would be to set localization settings for this procedure in the source code of QB and not to use Windows localization setting.