This error is caused by the library error on the Module page:
To fix the problem:
Open the "Eldorado IL.sam" file and go to the Module page.
At the top of the page, switch from CEC Performance model with User Entered Specifications to CEC Perfomance Model with Module Database.
When you see the error "Error: '' is not available in the library. Choose a different item." error, click OK. You may need to click it two or three times.
Choose any module in the library.
Switch back to CEC Perfomance Model with Module Database.
The module you are using is in the module library -- Canadian Solar modules are listed as "CSI Solar". You can choose the CS7N-705TB-AG module if you want to avoid having to type in the datasheet parameter values.