Can't enter Date of Birth after 2004

Hi there
I have a problem with my program
It keeps club data, and a date of births is essential.
It has worked fine for quite a few years, but now that people born after 2005 are involved - it has created a problem !!
If I enter a year after 2004, it will revert to that year (which can then be edited and changed, no problems !!)
ie - If I enter 2004 as year of birth (this is from a drop down list that starts at 1933 !!), all is fine, but, if I enter 2006 as year of birth, it reverts to 2004 in the database - (it will accept 2006 if it is then edited to that)!!!
I have been over the code heaps, but can’t understand it !!
Any ideas !! Very frustrating, and needed for the club data !!
I suffered a stroke a while back and am now just trying to maintain this for the clubs involved - harder to think clearly now
Thanks for your help !!

If you have to choose the year from a dropdown box, changes are the code that receives thar form data and stores it in the database, does some kind of verification.

Could you post that piece of code here?

Thanks for answering - just found the error !!!
So simple - but uor reply prodded me to look again !!!
Thanks heaps !!