Automation testing - Can sometimes not work inspite of all efforts, or take much more time ..

Doing an automation project can be sometimes fairly easy, it is just a simple matter of creating an objectives document, creating an execution plan, budgeting for the resources, making sure that the people committed to doing this are on the job, and that the plan is doing well. In a majority of cases, the project runs as per the schedule and the automation project gets completed.
However, this need not happen every time. Like any other project, there can be cases where the project runs into a lot of trouble or where there is something new being attempted, and the going gets rough. I have a personal experience of the same.
We had a project where we running into a shortage of resources for a testing case, and the case seemed to one where the testing was of a repetitive nature; hence, the project seemed to be one such where if we could setup an automation project, it would meet all the mission objectives. So, we got a person who was an automation expert, worked out all the objectives, worked out an execution plan along with a schedule, and started work.
We soon ran into problems that would disturb projects where the work is of a sort that was not done before. The project involved a situation where a large DVD was needed to be tested regularly. Each DVD that was manufactured had a small customization for individual clients, with the changes between the individual DVD's being very small. However, each DVD was needed to be tested thoroughly since each DVD was sent to individual clients, and it was not acceptable that any of the clients received a non-functioning DVD. The DVD needed to be put on a fresh machine, virus tested, the customization as well as the functionality of the application needed to be tested. The attempt was to create an image where many of the testing situations (including a virus check) were inserted, so that the test cases could be run automatically with a single resource just coordinating the work, and noting any errors if produced.
However, we ran into errors on many of the steps, since there did not seem to be anybody in the company who had done these sort of automation work before, and research on the internet did not seem to work either.