yes i had this problem and i was advised and this is no joke and it did actually work and i do it regually now asthe creaking drove me madyou use vasaline put it on a cloth and wipe it around all the door rubbers seals and it does stop it sound really stupid but it really works
Been down this avenue before!
The best thing to use for rubber seals is Silicone Spray.
Superb stuff that costs about £4.50 per can and does not dry out, like WD40 for example.
Halfords do there own brand as well as the one above.
Just spray this onto a cloth and place it upon the rubber seals. Last for ages.
Used this stuff as well to keep the windows moving up and down smoothly.