Error when installing Membership Pro

I have just bought and tried to install Membership Pro but receive this error message (it is on my localhost)
Warning: constant(): Couldn't find constant JPATH_ in C:\xampp\htdocs\arl\libraries\cms\installer\adapter\module.php on line 205

This is running on Joomla 3.4.1. I then turned error reporting to none and re-installed the component, and am about to test it. But I thought you should know about the error.

Hi

This is something with Joomla core installation process and I think they will fix it in version 3.4.2. It doesn't affect the extension, so don't worry about it

Tuan