Lossy DNG files exported by LightRoom 4 seem to crash.

The call stack is:

#0 0x0000000116801719 in LibRaw_file_datastream::jpeg_src(void*) at /Users/tbrown/Documents/ProjectsOnOne/Suite6/LibRaw/src/libraw_datastream.cpp:280
#1 0x0000000116793de9 in LibRaw::lossy_dng_load_raw() ()
#2 0x00000001167c0751 in LibRaw::unpack() ()
#3 0x00000001167bc9de in libraw_unpack ()

when calling this line of code

jas_file = fopen(fname(),"rb");

The fname() returns a garbage string so that the fopen fails and then crashes soon after.

I am using the USE_JPEG8 flag when compiling. I have upgraded to the latest version of the jpeglib. Is there something else I need to do to get this working

Thanks for any help you can give.