After reading this thread and overriding/deleting the 0 on the form (CD version), I was able to e-file my MD taxes this morning. I had already e-filed my federal on 2/1 and received my direct deposit refund last night. I have determined that the Form 8582 error was directly related to the 1099K I received from Paypal for the first time this tax year for personal items sold on line and paid for through Paypal goods & services (not friends & family). The federal entry of Schedule 1, Part I, line 8z shows that 1099K amount as 0 and transfers to the MD form which doesn't know what to do with it yet
