Copied below, I have a series of monthly cash flows for a project. The IRR
function is giving me a "#DIV/0!" error, while the XIRR gives me a return of
10.19%. However, when I try to double check that return by discounting each
cash flow individually (NPV), I arrive at a rate of 9.75%. So I have two
questions for all you excel brains out the
1) Why is my IRR not working when XIRR is? and
2) Why is my NPV check not matching the XIRR result?

I've been searching through microsoft excel's help section and poring over
various forums without any luck. Any advice would be much appreciated, and
allow me to stop bashing my head against the wall!

Thanks,
Zach

12/1/2005 ($128,931,571)
1/1/2006 ($1,431,571)
2/1/2006 ($1,431,571)
3/1/2006 ($1,431,571)
4/1/2006 ($130,363,142)
5/1/2006 ($2,863,142)
6/1/2006 ($2,863,142)
7/1/2006 ($2,863,142)
8/1/2006 ($2,863,142)
9/1/2006 ($2,863,142)
10/1/2006 ($2,863,142)
11/1/2006 ($2,863,142)
12/1/2006 ($621,565,535)
1/1/2007 ($45,536,678)
2/1/2007 ($2,822,847)
3/1/2007 ($2,458,944)
4/1/2007 ($2,170,616)
5/1/2007 ($1,883,945)
6/1/2007 ($1,598,931)
7/1/2007 ($1,315,573)
8/1/2007 ($1,033,872)
9/1/2007 ($753,828)
10/1/2007 ($475,440)
11/1/2007 ($198,708)
12/1/2007 $76,366
1/1/2008 $349,784
2/1/2008 $440,556
3/1/2008 $440,556
4/1/2008 $443,149
5/1/2008 $444,446
6/1/2008 $444,446
7/1/2008 $444,446
8/1/2008 $444,446
9/1/2008 $444,446
10/1/2008 $444,446
11/1/2008 $444,446
12/1/2008 $444,446
1/1/2009 $444,446
2/1/2009 $444,446
3/1/2009 $444,446
4/1/2009 $444,446
5/1/2009 $444,446
6/1/2009 $444,446
7/1/2009 $444,446
8/1/2009 $444,446
9/1/2009 $444,446
10/1/2009 $444,446
11/1/2009 $444,446
12/1/2009 $2,228,768
1/1/2010 $2,332,674
2/1/2010 $2,413,092
3/1/2010 $2,539,117
4/1/2010 $2,643,023
5/1/2010 $2,746,928
6/1/2010 $2,850,834
7/1/2010 $2,969,999
8/1/2010 $3,089,164
9/1/2010 $3,208,128
10/1/2010 $3,327,293
11/1/2010 $1,400,293,587