Just in case someone else has the same issue - I had to create a new Role for Suitescript Developer (Answer Id: 51761), then login to NS with that role, go to Home> Settings > Manage Access Tokens and create a token key / secret pair for this role. Then I went to Eclipse IDE and changed my authentication method (Netsuite > Manage Accounts > Manage Authentication > Save token - and save the key + secret generated earlier.