I am in the Reports and Dashboards Module. I am at the section where the exercise is to creat a Joined Report. When I click on "Tabular Format", "Joined" is missing as an option. Did I miss a step before selecting "Joined", or is there another reason why it would be missing?

Hi All,
We are receiving an internal server error. when I go to (any) Permission Set, Apex Class Access then hit 'Edit' we are facing this issue. How can we overcome this, please assist.

Error: An internal server error has occurred An error has occurred while processing your request. The salesforce.com support team has been notified of the problem. If you believe you have additional information that may be of help in reproducing or correcting the error, please contact Salesforce Support. Please indicate the URL of the page you were requesting, any error id shown on this page as well as any other related information. We apologize for the inconvenience. Thank you again for your patience and assistance. And thanks for using salesforce.com! Error ID: 1488824837-18844 (-1270687048)

I'm having an issue on step 8 of the LIghtining Experience Trailhead.  I've loaded all the objects and the error still says: "Challenge Not yet complete... here's what's wrong: 
Please check that all of the relationships are maintained for Opportunity Contacts and Adventure Packages that you upload from the spreadsheet."  I have all the explorers on the Adventure packages, where else would it be looking?

Thanks!