Whilst I'm am not including remote files, I too am getting the same problem since I installed php triad on my windows 2000 systems.
I'm getting a similar include error message, except that the include files are in the same directory as the file that is including them.
This problem didnt occur when I installed apache/php and mysql manually. It only occurred after my hard disk crashed and i installed php triad.
I'm just wondering if anyone with php triad also has this problem.