I just installed GnuCash yesterday, and I had the same problem of aborted application startup. I tried to start it from the terminal, and noticed that the errors had to do with permissions problems. I tried running it as root, which worked beautifully. Of course, I didn't want to do my accounting as the super user, so I was happy to find the tip from sledgehammer above. I just reinstalled slib and now my regular user login can run GnuCash! No need to install webkit.
(Of course, I had to chown my GnuCash file back over to my regular user account.)
I am also what you might call a "silent" FOSS user. I don't work in the tech industry - I'm a neurology resident. I started using the GIMP back in undergrad, then discovered Mozilla, OpenOffice, and other Free/Open apps. I even read the GNU manifesto. Eventually I started playing with Linux, and actually VectorLinux was the first distro I installed and kept. Interestingly, my killer app for Linux was GnuCash, because there wasn't a Windows version back then. I've been doing all of my accounting with it since early 2004. I migrated my wife over to Linux about 5 years ago, and she is happy with it too.