The original, clear, Paterson reels were difficult to load but the white ones are made from a self-lubricating plastic and work pretty well as long as they are perfectly dry.
The only major issue is caused by a few early Leicas which rolled the film onto the take-up spool emulsion out. This gave the film a reverse curl which made it impossible to load!
Have you tried cutting the leading edge of the film between the sprocket holes, not through them. Then trim off the leading corners just a touch at 45 degrees as this will stop them digging into the sides of the grooves so much.