Ryanair Passport dob error when checking in

Call me thick and to hopefully save me an extortionate phone bill... on the Ryanair check-in page, just as I pressed the button that says 'no changes can be made after this point', I saw my date of birth flash before my eyes as a month early ( I really hate those drop down menus). I printed out my boarding cards and there is no reference to the passport. But, what does that barcode hold? Any ideas chaps? Thanks

Panic over. I rang the UK number (I have discovered that Neuf don’t charge you to call chargeable UK no’s, why?, I have absolutely no idea), waited about 5 minutes, a very nice Eastern Block lady called Veronica changed the date of birth for me for no charge. PHEW!