After reading up on failures associated with I.S. projects it is pretty apparent what has the greatest risk involved in it within the project.
At number 5 would be staff turnover, which could cause problems for communication within the project.
At four would be poor planning of the project.
Three is the changing of project scope, with lack of proper communication.
Two is the lack of communication between the project managers and the end user during the project.
At number one would be the lack of commitment from top managment. Without this ther is no drive in the project.