Vlookup Error / Imported Data Format

I am trying to bring the values in column B of "Forum Data 010512" into column O of "Forum Import 010512" using a simple Vlookup. The Vlookup I'm using in column O is =VLOOKUP($F:$F,'[Forum Data 010512.xlsx]Data'!$A:$B,2,0). The result is #N/A even when the data file has a value in column B.

I suspect that this has something to do with the fact that the information in the data file originated from an outside source. I have tried scrubbing/formatting the data nine ways to Sunday but cannot get the vlookup to give the me values.

Someone please help me before I throw myself out of the window!