I should have known back in 1968 when I was a trainee programmer learning IBM /360 assembler that it would help me almost 50 years later. Trying to work out what went wrong with my curve creation, I noticed that I had used quiet long names. 32 was one of the magic numbers back in 1968, so I reduced the file names to under 32 and it worked. It would appear that verbosity can be a curse.