It's safe to say this isn't good news. Nothing is certain yet, but in September, NASA pushed the launch date of the telescope back to between March and June of 2019. Now, it looks unclear whether that goal can be met. The 31-page long report details myriad technical issues that have put the project behind schedule. The contractor, Northrop Grumman, is trying to catch up but "the contractor has increased its daily work shifts from two to three and is now working 24 hours per day on spacecraft integration, which further limits schedule flexibility."
With the delays that have cropped up, if nothing else goes wrong, there will only be one and a half months left in the launch window by the time the telescope is ready. And because this is a very delicate, very technically complex device, there is certainly more that will go wrong. The GAO estimates that because of this narrow time frame, "we believe that the rescheduled launch window is likely unachievable."
The time issues are made even more complicated by the fact that the James Webb Space Telescope is running into its budget cap, which was mandated by Congress back in 2011. It's not clear what will happen from here; the next step is for the managing board of the James Webb Space Telescope to meet and determine whether the project can, indeed, be completed on time.