Gilliam's struggles to make the film were well documented in a 2002 documentary entitled "Lost in La Mancha." Here is an excerpt from my review which basically sums up the whole shebang:
"Terry Gilliam was able to start shooting his dream project about Don Quixote "The Man Who Killed Don Quixote," in 2000, starring Johnny Depp and, in the title role of Don Quixote, French actor Jean Rochefort. That was the only positive news that happened it seems because, due to budget problems, shooting schedule problems, horrible weather problems, and the unfortunate ill health of actor Rochefort, the production was a disaster before production even began. There were only 6 days of shooting before the entire thing was scraped and "The Man Who Killed Don Quixote" was completely abandoned."
"Lost In La Mancha," a documentary that captures the first eight weeks of pre-production (another nightmare experience for Gilliam) to the disastrous six-day shoot that followed. It is frustrating to watch because one moment we see Gilliam all giddy and ready to go, and the next minute he's having a mental breakdown over the sheer bad luck happening all around his dream project."
"A feeling of what could have been exudes throughout the picture, the terrific sets, costumes and production design that were created for the movie (including perfectly synchronized Gilliam-esque life-size marionette puppets) give out an over all feeling of what might have been. Maybe there will be a day when it can be realized, but it seems like the dark cloud looming over this picture at the moment is too compromised to just easily go away"