DXF IMPORT

Hi All!
I'm Having troubles trying to import DXF Files into UCCNC.
problems seems to be that UCCNC isn't able to understand some lines of code from an standard DXF file even with R12 ... R14 versions of DXF files.
there are so many lines that pop up error that is impossible to erase theese lines for every time
the same files are well recognized by ESTLCAM or other software
th error is:
error reading line number:"nnn" line: $DIMEXO
deleting this line and saving the file will give another similar error line

Any help or thougth would be great

My Version of UCCNC is 1.2111
STEPCRAFT INSTALLER VERSION 3.5
Machine D840
CAD SOFTWARE RHINO 7