At last, definite progress. I've identified the line in the program that gets upset when it encounters a read-only file. Unfortunately according to all the manuals I've read it shouldn't get upset as it's not trying to write to the file. I guess it may take a couple of days to come up with a fix. Also, some of you are reporting problems without read only files. That may be a strange quirk of the same problem or it may be a separate problem, only time will tell. Please send details of step by step tests so i can have more evidence to go on.