Eternity Puzzle Solver: Is it working?

I've been thinking about the Eternity II puzzle, I mean $2 million would be worth putting in a little effort. I know I am not going to solve it, and I am not going to win the money, but it has sucked me in anyway and I spent the last few days working on it. I did some thinking, and then I wrote some code, and then I realized I didn't really know what I was doing, so I thought about it some more, and Sunday morning I woke up early and wrote down my plan (in English). Then I sat down to write the code, there were a couple of hiccups, but I got those squared away and I fired it up yesterday evening. It got through the first column without any trouble, but once it got to the top edge it seemed to get stuck. It's been running the better part of a day and it's still stuck on the top row. So is there a bug in the program that is making it try the same tile over and over again, or is just really taking that long? I went through the program again, and rearranged some of the code, but I didn't find anything that could have been causing a real problem. Given the kind of problem, it could very well be taking that long. I mean it will take an eternity to get the complete solution, so what's a few hours or days to complete one row?

I suppose what I need it some kind of stop command that would allow me to stop the program and examine the results so far, and is satisfactory let it resume. This is going to take some finagling. Probably have to use some POSIX calls or something.