Incorrect date display in calc for xls files

Whenever I open my financial reports in libre calc the date fields are all displayed as: 31/12/1899 00:00:00.
Microsoft Office displays all the dates in the file correctly.

I uploaded the file (with the irrelevant info omitted):
link text

EDIT:
Apparently, libre calc resets all the dates to null values when it reads the file.
I took another xls file and made sure the dates were all valid then used MS Office to save it as an xlsx.
Openning the xls file with LO calc resets the date values. To my surprise, openning the xlsx files worked, the dates didn’t reset.
Here’s the xls file for your viewing pleasure (watch how the dates are valid before openning the file).
It’s a bug in calc’s xls support, I should just add it to LO’s bug tracker, Right?

1899-12-31 is the NULL date, seeing that means the cell does not contain a serial date value or a 0 value formatted as date. I can’t see the file you linked, browsing there just tells me “browser does not allow data to be written” and I’m not willing to change any browser settings for that mega.co.nz domain…

I know it’s the null value, It shouldn’t be the null value.
Openning it with Microsoft Office shows all the dates just fine.
As for the file, Here it is on another file sharing file: here

Whatever you did, that file is an Excel-XML file and contains literal 1899-12-31T00:00:00.000 for each cell:
1899-12-31T00:00:00.000
If that is the data file you loaded then Calc just displays what’s there.

Have to agree with @erAck. When I open your file in Excel Starter 2010 it complains “not the file structure like the extension” and there are no dates displayed only numbers “0”.