What is your HTML source code for creating the form? Could you post it?
For 2nd problem, what version of PHP are you using? Your message box shows a lot of strange characters, which looks like your PHP isn’t correctly configured or maybe you’re using some PHP accelerator or third-party extension?
Yes, you have to create a new folder with all files from the kit.
It’s up to you. But online validation requires an Internet connection. If there is no Internet connection, and the EXE tries to validate, it will consider the validation as failed, and execute the action you configured in that case.
The maximum is 2. It doesn’t depend on on the quantity ordered by the customer but, if you are familiar with WordPress API, it’s possible to modify our code to implement that.