I'm having some problems using the SUMIF() formula - if I generate a cell
using it and then open the workbook in Excel 97 (or 2000)
the displayed cell value is #VALUE!. However, if I look at the contents of
the cell, the formula appears to be set correctly, and if I double-click
on the cell, or hit the function button followed by OK, the cell then
recalculates correctly.

I should have said that if I do a manual recalculation  within Excel (
tools | options | calculation | manual, F9) the cell is still not
updated - I have to double click on it as described below.

I'm using 1.7-dev and JDK 1.3.1 with Excel 97. 

Attachments are:
poi.xls, poi.out - xls and BiffViewer from POI
hand1.xls, hand1.out - xls and BiffViewer after loading into Excel 97 and 
saving unchanged
hand2.xls, hand2.out - xls and BiffViewer after loading hand1.xls, double-
clicking on formula and resaving.

diff between hand1.out and hand2.out:

$ diff hand1.out hand2.out
1687c1687
<     .value           = NaN
---
>     .value           = 0.0
1702c1702
< 00000000 45 00 00 01 00 00 C0 00 C0
---
> 00000000 25 00 00 01 00 00 C0 00 C0
1717c1717
< 00000000 45 00 00 01 00 01 C0 01 C0
---
> 00000000 25 00 00 01 00 01 C0 01 C0

In context:

============================================
Offset 0xa41 (2625)
recordid = 0x6, size =47
[FORMULA]
    .row       = 2
    .column    = 3
    .xf              = f
    .value           = 0.0
    .options         = 0
    .zero            = -52428800
    .expressionlength= 25
    .numptgsinarray  = 4
Formula 0=AreaPtg
firstRow = 0
lastRow  = 1
firstCol = 0
lastCol  = 0
firstColRowRel= true
lastColRowRel = true
firstColRel   = true
lastColRel    = true

00000000 25 00 00 01 00 00 C0 00 C0                      %........

Formula 1=org.apache.poi.hssf.record.formula.IntPtg@60be38
00000000 1E B8 0B                                        ...

Formula 2=AreaPtg
firstRow = 0
lastRow  = 1
firstCol = 1
lastCol  = 1
firstColRowRel= true
lastColRowRel = true
firstColRel   = true
lastColRel    = true

00000000 25 00 00 01 00 01 C0 01 C0                      %........

Formula 3=<FunctionPtg>
   field_1_num_args=3
      name         =SUMIF
   field_2_fnc_index=345
</FunctionPtg>
00000000 42 03 59 01                                     B.Y.

[/FORMULA]

============================================