Pretty sure I've heard of this before... might depend on what version you're playing. I know that in the past, not everything was calculated in the weekly report. I think maybe the girls' living expenses weren't... and possibly girls bought items when they didn't have any gold, so it would take out of your pool.
A while back, I think there was also a version in none of the earned money was adding up.
I think I also saw a problem like this once with trying to unzip one version over another. If you tried that, you might look at unzipping to a fresh folder.
If there isn't a bug in the game itself, you can use the WMEditor to change your starting gold in the config file to make things a bit easier.