SUMMARY: Excel sees combo box values in one cell and doesn't see it in another

I'm running Index and Matches based off of values obtained from ActiveX Combo Boxes in Excel 2007. Before I put in combo boxes (to make the font size larger), the formulas all worked. After putting in the boxes and linking the appropriate cells, some work, some don't. Here is one where I am having the issue. My setup includes the following cells:
L4: Hose Type (ComboBox1)

L5: Size (ComboBox2)

L9: Fitting (ComboBox3)
The drop-down lists in each box work properly. In column O, I'm populating part numbers. In column G, I'm populating costs. In O4, for instance, I index the Hose Type (L4) and Size (L5) to return the part number. In O5, I index the Fitting (L9) and Size (L5) to return the fitting part number. The index formulas from L4, L5, and L9 are each working for O4 and O5. Here are the formulas, in case they are helpful:

O4: =IF(ISBLANK(L5),"",INDEX(AU3:BL13,MATCH(L4,AU3:AU13,0),MATCH(L5,AU3:BL3,0)))
O5: =IF(ISBLANK(L9),"",INDEX('FTG INDEX'!A26:R122,MATCH(HOSES!L9,'FTG INDEX'!A26:A122,0),MATCH(HOSES!L5,'FTG INDEX'!A26:R26,0)))


When looking at L4, L5, and L9, the values from the combo boxes are in each cell. The problem is that I'm trying to index using these same cells in G10, and Excel doesn't see the values. In G10:

G10: =INDEX('FTG INDEX'!A4:CF21,MATCH(L5,'FTG INDEX'!A4:A21,0),MATCH(L9,'FTG INDEX'!A4:CF4,0))

This returns the message that "A value is not available to the formula or function." G10 worked properly before I put in the control boxes, so the formula works. So it seems that one cell can see the Values but another cell can't. Any suggestions?

Thank you very much!
-Kevin-