They were generated by a program that one of our customers sell with his laser machines. All of their laser run HPGL only, and these files are typical of what gets generated.
As stated, these post perfectly on our current control which reads in HPGL directly (and G-code) and uses it as a cut program.
I think I sent these files to you converted to DXF also. I found an HPGL to DXF conversion utility to do it, and when converted, there are a lot of lines that don't intersect. Your old LazyCam will load those perfectly with the filter set to 0.001", the new LazyCam won't run them.