Lots of things to consider when sewing with metallic threads:
Firstly buy Metallic needles in a range of sizes so you can try different ones. They have a larger eye than regular needles so help to reduce friction and shredding. If you can feel the metallic threads before you buy them. The smoother they are the more easily they will feed through your machine. A rough metallic thread will tend to resist moving through the machine. Try reducing your top tension (lower number) to allow the thread an easier passage through the tension disks. Lubricate the thread with a non staining silicone lubricant such as 'Sewers Aid'. This is put directly on the spool of thread and helps to reduce friction. Don't have your stitch length too short. Longer and it allows the thread to show itself off, and also reduces the friction/number of times the working thread passes through the eye of the needle.
Don't use metallic thread in the bobbin. Choose a similar coloured thread and try either 'Bottomline' or a 50/2 cotton (such as Aurifil) in the bobbin.
Don't sew at a very fast speed as again this adds to the friction and might encourage thread shredding.