Hello Alessandro,
I verified your project in KDS 3.0.0 and I found out the issue that cause the error. The FLASH1:FLASH_LDD component contains User memory area 1 that overlap the FLASH_CONFIG area (0x400 - 0x410), see the following screenshot:

You cannot use the FLASH_CONFIG area for your user data.
When you set the Address to 0x400 and the Size to 0x1F0 (in the User area 1 of the FLASH1 component) and generate Processor Expert code the error will be cleared in the Problems view.
Please, fix this issue in your project and your project will work properly.
I will report the issue to the Processor Expert development team (a proper error shall be reported in this case) .
Best Regards,
Marek Neuzil