It is a really annoying machine at times!! Sometimes it just seems to not like a type of thread or a type of binding fabric and there is not too much you can do about it.
Some things to check that I could think of...
Release the tension on the presser foot by turning the nob at the top of the machine. It needs to be released quite a long way if your binding is a thicker fabric.
Try having the same type of thread for all three.. doesn't always matter but sometimes it can make it spaz
For binding make your stitch length quite long
Make sure the front of the binder isn't touching the presser foot.. have it just in front but not touching as that can stop it running easily under
Don't use the bit on the right end of the binder to loop the end of the fabric through.. push it out the way or remove it totally. Hold the end of the binding with your right hand.. that way you can make sure it doesn't twist and you can easily increase or decrease the tension.
Take a huge long length of binding and run it through while you have a play...