The ClarisWorks 4.0 QuickHelp description for HLOOKUP (Horizontal Look Up) has an error in the sample spreadsheet. The last line shows that =HLOOKUP (A8,A1..E3, 1,0) would return the value 55. Since the lookup value in A8 was "F", and there were no F's in the data, the formula would have returned #N/A!
If the lookup value is changed from "F" to "E" in cell A8, the result of 55 will be correct.