Lots of feedback available on Furling Mains. I have a 2006 Bene 343 with the original furler and Neil Pryde Main with vertical battens.
Make sure the mast is straight.
I keep a lot of tension on the Main Halyard.
Let out some slack in the Mainsheet and vang
I use a topping lift in addition to the vang.
I usually unfurl the sail heading downwind - it lowers the apparent wind and keeps the sail from flogging. I frequently furl the sail downwind as well - helps keep tension on the sail while furling.
I always keep a wrap of the furling line on a winch. Since I have the Spinnaker Halyard winch, I use both winches when launching and retrieving the sail My lines are setup to enable using each winch - furling line on port, outhaul on starboard.
Check the size on your furling line - mine is getting replaced with one size smaller due to friction between the line and the metal sleeve on the backside of the furler spool.
Make sure your outhaul slides smoothly under load.
Check the lead angles on both lines. Also the blocks supplied by Bene have plastic bushings so don't spin well especially if full of gunk.
Keep tension on the sail when furling.
I've only pulled my sail twice and removed the battens, but getting the flap on the batten pocket tucked back in is a problem unless you use another batten or something similar to keep the velcro from grabbing. It would not take much of a wrinkle there to hang up.
If you do remove the sail - tie a 1/4 or 3/16 line onto the lower shackle or through the hole and pull your furling line and the "sail" line to see how well your furler spins - gunk in the bearings or friction on the line are the biggest suspects. Also check how the main halyard is attached to the top shackle - a big knot will rub inside the mast sleeve.
Bob probably knows twenty other things to check.
Joe