Don't use the backup feature. It's incomplete and causes additional crashes if you have Pets or later installed.
WooHoo is a program that shows you what a package file contains, or it will install a sims2pack. It will not delete your files if you choose to use it. Install is as simple as extracting the zip and double clicking the icon. It comes in its own folder that you can put anywhere, I put mine in Applications since its an application.
To uninstall simply delete the folder.
Please elaborate on the crashing and what you were attempting to do with it. As the first post stated, if you are trying to open files created with the Pets EP or later the program will crash because work stopped with it prior to that EP. And I suspect the test function would crash with those packages as well. There was at one point an issue with too many downloads and running the backup feature, I don't remember if it was ever fixed.
But on that note, it will install any package files, except official exchange ones, something about the size of them I think it was.
