The months, weeks and days displayed on my ticker are incorrect? How do I fix it?

It's correct, it's just that the result of calculating months, weeks and days can seem counter-intuitive because there isn't an even number of weeks in a month. The way it works on Lilypie is to count the number of months, and then divide the number of days remaining into weeks and days. The best way to check it is visually, with a calendar.

For instance, using a 2nd birthday ticker on Lilypie for a child born on the 9th of May, 2004, and looking at the ticker on the 25th June, 2005. On the 9th of June, the child was 1 year, 1 month old. There are 16 days between the 9th of June and the 25th of June so the Lilypie baby days will display 1 year, 1 month, 2 weeks and 2 days.