Receiving #N/A as Result for a Formula

I am hoping someone can help me. I have a Array Lookup formula in a cell. The Fomula is:

=LOOKUP(H2,F2:G32)

The Array Table is:

Budget
Code Program
1 Medical Officer of Health
2 Manager Budget
3 Child Health
4 Dental
6 Media
7 Epidemiology
9 Vaccine Preventable Disease
11 Munn-Health Protection Disease
12 Sexual Health
13 Handley
14 Manager (Hart)
15 Health
16 Health Protection
17 Communicable Disease
20 Team
22 Safe Food Protection
28 Health Promotion
30 CD
32 Cancer
34 Mgr-Clerical Services -
35 Administration -
36 Clerical Support
37 E.A. Management
47 Small Water
48 Prevention of Falls
50 Tobacco-Basic/Policy Falls
54 SFO-Bylaw & Falls
58 Ontario Healthy Smiles
66 Priority Populations
70 Speech and Language
76 Panorama

The formula works when I type a number into the column just before the column with the formula in it, the corresponding progam name displays but until I type in the budged code number the #N/A message displays in the column I have the formula in.

I do remember having this issue with a spreadheet several years ago and I know I found a solution with the help of someone on the forum but I must have lost what the solution was. I would like the cells to remain blank until I enter the corresponding budget number budget number