Dynamic Named Range List not being updated dynamically

I have an excel 2003 workbook with 6 sheets on it. The 6th sheet is used as a repository of values that are to be used as lists on the other 5 sheets.
I made 3 named ranges and was able to use it successfully on the 5 sheets, but as soon as i tried to modify one(Customer) of the named ranges to go the Dynamic Named Range route, it simply doesn't want to work.
What happens is that when i enter a new value into a cell with the drop-down list, it just takes the value in that cell, but doesn't make any addition/change to the existing list on the "repository" sheet or the drop down list. I have disabled the error warning, so it doesn't throw me an error when i enter an unique value into the cell, but thats about as far as i can get. I need it actually add the unique value into the drop down list, so i can later use the new value(from the drop-down list) on subsequent cells.
I have attached a screen-shot of the list that i want to update dynamically when a user enters a unique item into the cell with drop-down list.
The formula that i'm currently using(which doesn't want to work) for the named range is below:
=OFFSET('Drop Down Lists'!$A$3,0,0,COUNTA('Drop Down Lists'!$A:$A)-2,1)

Can you tell what i'm doing wrong?
Thanks in advance for every suggestion.