Cell format errors appears in Excel 2003 but not in Excel 2000

**@nki$achi** · 24-01-2012

I am at a lost. For a year now, I've been developing an Excel 2000 workbook. All has been well until a month ago, when I hit the nasty "Too many different cell Formats" error. This was accompanied by several Excel 2000 crashes as I tried to reduce the number of Formats used in the Sheet. I was finally able to reduce the number of formats, and I've continued development of the workbook - but it seems that Excel 2003 fails to open the Workbook - a problem which is not present in Excel 2000. Here is all I know of about this :

Excel 2000 has NO problem with the Workbook.
Excel 2003 can load the workbook ONCE, but if you Save & Reload in Excel 2003 - then it will not work.
The workbook does NOT use ANY macros
The workbook does NOT use User Defined Functions
The Workbook does NOT use any Add-Ins
The workbook uses only simple functions, from vlookup to trunc. Nothing fancy.
The workbook has alot of Formatting - which is lost when 'repairing' it.
When double-clicking on the Workbook to open it (using Excel 2003), I will get "Opening .. (filename)" then there is no progression and then "Microsoft Office Excel has encountered a problem and needs to close. We are sorry for the inconvenience".
I have tried "ExcelFIX Pro Demo v4.20" to see what happends. No errors are detected.
I have tried "Advanced Excel Repair" and It does'nt help
IF i delete one worksheet in Excel 2000, save - then I can reload in Excel 2003. BUT if i save from Excel 2003, the next time I reload - BOOM
If I try saving (from Excel 2000) in Excel 97 format, then Excel 2000 reports: "A Formula in Cell (Name:tSel_WeaponFocus) could not be converted because it contains a function that is not available in the file format to which you are saving. If you continue the save, the Formula and result will be saved, but the function itself will be converted to an error value." - First of all, "tSel_WeaponFocus" is a 3 cell table which uses a list for the input (as Data Validation) - and worst (or best ?!) of all, is that when I
reload back in Excel 2000 the resulting Excel 97 file, that section works correctly as if there never was any reported error. Doh. Note that "tSel_WeaponFocus" is the LAST named cell I got... (does this means something ?)
In both Excel 2000 and 2003, I tried selecting all worksheets and copying them to a new workbook - no luck there.
Here is another weird thing: Sometimes, when starting excel in Safe Mode, the workbook will load correctly - I've also noticed that using FILE->LOAD instead of double clicking will allow the workbook to load normally - but I an't figure out any pattern.

Now, I'am already aware I could start from a previous (working) old version, but that would set me back at least ONE MONTH of work. Is there ANYTHING I can do that would allow Excel 2003 to be able to STOP crashing while opening a workbook created in Excel 2000 ?!