i have the super glide i think, or something like it and it gave me fits with myh 60x60 quilt when doing free motion quilting.Since you're not doing fmq and just doing a straight stitch, can you remove the extension table from your machine. you don't really need it.
if not,hold the end of the fabric up as you feed it under theneedle. that should help. and perhaps a longer stitch too. that helps the fabric move easier.----
oh i just read about the tissue paper hint. great hint too.
i had trouble with some pieces and put paper underneath the fabric and it worked like a charm!!