Not sure that LCam will read all the various DXF's in Autocad, but I just saved a drawing under the 2007 DXF format (Using AutocadLT 2009 Student version) and LCam read it without any trouble. But, it wasn't text file, just a file with lot of angles and lines.
I am pretty sure that I have saved under other versions of AC and retrieved without problems since I don't always remember to use the R12 DXF format.
I have not been successful in bring DXF text into AC - nor has using the Text application in AutoCad produced TEXT that can be read by LCam. For this I generally use two programs - CADX11 and DeskEngrave. Using both I have developed text for several pieces that I have been working on. DeskEngrave (a free program) will also produce a DXF file that LCam reads without any problem.
CADX11 is also a free program (although licensed version will handle much larger files).
Bob @ BobsShop