I am trying to use the following formula to determine wether an event has
occurred in 2004 (when it was scheduled) or if it will be pushed to 2005
(after 1/15/05), anything with a TBD needs to be pushed to 2005, and any
blank cells should be ignored. The formula is breaking when any date with
2004 appears.

=IF((ISBLANK(E3))=TRUE,"",IF(E3="TBD","2005",IF(E3 1/15/2005,"2005",IF(E3<=1/15/2005,"2004",""))))

here is a look at the spreadsheet:
A B C D E
1 Store Project Start End Actual
2 Atlanta Remodel 10/26/04 1/15/05 2005
3 Reset TBD TBD 2005
4
5 Chicago Remodel 9/21/04 12/15/04 2005
6 Reset TBD TBD 2005