As far as wet basements go, Franklin Park is off the Des Plaines River. I know about this as well, I live 600 feet away from the River. We don't experience flooding as we are on high ground (the floodplain goes east from where we live and we're on the west bank). Some parts of Franklin Park are prone to flooding. There are many ways to deal with basement water (flood control systems, sewage back up prevention, etc.). In all but the most extreme cases, it can usually be mitigated. You can find out the history from the village and see what areas have flooded in the past. Last september is a good marker to look at.
The deal could have very well fallen apart because of a condition issue, but it's also likely that the buyers were just waiting too long for third party approval and found something else.