After reading the suggestions a thought occurred to me. Do you know what the thread wax is? It comes in a round shape and you pull your thread through it before sewing (hand sewing) and it keeps the thread from knotting. Wal Mart carries it. I wonder if you pulled your thread through it (using a needle) somewhere at the top of the machine and then thread as per your machine. I wonder if this would help the thread slide through the glue. Have you tried a heavier thread and a larger needle? I know they leave holes but you could press them out. Good luck.
Let us know what you do to fix this. Thanks. Yolanda Wood River