Similar tothe one in post #2? <g>

I have played with the prog to replicate the error, and cant do it either. The only things I can think of is that the costs have become time related, and somewhere there is a tiny difference in calenders, although this seems improbable at best or that there is a prior resource with a weird calender.
Have you tried on a different computer? A quick input of the base programme would show it up, if values didnt change it woul dsuggest that there is a possible error in global settings.