The result of below XIRR calculation is very weired.

Apr 5, 06 16328
Oct 2, 06 16096
Jul 3 07 11251
Nov 1 07 71414
Dec 3 07 79637
Jan 2 08 13845
Feb 1 08 12610
Sep 17 08 -175691

Xirr answer: 2.98E-09

But if I change Sep 17 08 cash flow to -189000, XIRR come correct answer
-14.3%.
Any clue.
Thanks.
Janven