Saw your thread in the 'Zero Replies' section and wanted to give a bit of input, though no guarantees my advice will help
It *looks* like there is a missing header file(s), even though I see no error of 'File not found'.
What I would do if I were having this problem (and I have many times) is look at the beginning of the sourcecode (for example start with dfa.c) and see what header files are trying to be included with the #INCLUDE statements, and verify that they are all present and accounted for on your machine. I suspect that since all of the errors seem to involve 'flex-this' or 'flex-that' that the missing file is part of the flex package, and may well be right there in the directory with the source code. You may need to add an extra include path for the linker, to tell it where to look for the files it is seeking.
Hope this helps,