The version 2.1.3 is bugfix stable release as any other minor releases. This version does not have any problem related to this thread. I have just tested installation from scratch - no errors both during install nor Direct Invoice entry, so - as I said - I don't know the reason. Maybe this is something related to your Win MySQL installation or version (I use only Linux), but FA is always thoroughly tested before release also on Windows by Joe.
AFAIR the problem fixed was that user was allowed to delete some data from sample database content, which should not be deleted, which in turn lead to this databse error. You can find thread related to this issue somewhere on the forum, but as I said this was finally fixed in FA 2.1.3.
I installed the default and then created my own company from the setup page option - as explained in the forum. I used the en_US-new sql script to create my company. Could it be that there is a problem with the sql script?
I'm not sure I understand you right. What was the reason to create new company after installation, when all was working fine? After installation you have en_US-new.sql just installed, so for single company setup based on en_US file nothing more is needed.
Janusz