Yes, I believe that's the problem.
Exact wording of the feat in 3.5 includes the following: "you may choose to subtract a number from all melee attack rolls and add the same number to all melee damage rolls. This number may not exceed your base attack bonus."
Since your BAB is 0, even 1 would exceed your BAB.
If you want to test it. Use the console to level up real quick and see it if appears. Just make sure you don't cross-class into a class that also give no BAB at level 1
