Error when I try to start server

Here I’ve copied the error message in my terminal when I try to start server. Any help would be appreciated!

Path must be a string. Received null TypeError: Path must be a string. Received null at assertPath (path.js:7:11) at Object.join (path.js:1211:7) at EmberApp.index (/Users/DustinWalker/Desktop/collegesaves.com/node_modules/ember-cli/lib/broccoli/ember-app.js:687:24) at EmberApp.toArray (/Users/DustinWalker/Desktop/collegesaves.com/node_modules/ember-cli/lib/broccoli/ember-app.js:1663:12) at EmberApp.toTree (/Users/DustinWalker/Desktop/collegesaves.com/node_modules/ember-cli/lib/broccoli/ember-app.js:1686:38) at module.exports (/Users/DustinWalker/Desktop/collegesaves.com/ember-cli-build.js:22:14) at Builder.setupBroccoliBuilder (/Users/DustinWalker/Desktop/collegesaves.com/node_modules/ember-cli/lib/models/builder.js:56:19) at new Builder (/Users/DustinWalker/Desktop/collegesaves.com/node_modules/ember-cli/lib/models/builder.js:30:10) at ServeTask.run (/Users/DustinWalker/Desktop/collegesaves.com/node_modules/ember-cli/lib/tasks/serve.js:24:55) at Promise.resolve.then (/Users/DustinWalker/Desktop/collegesaves.com/node_modules/ember-cli/lib/models/command.js:242:46)