Here is the command line and the output. 

mris_flatten -1 -w 0 -distances 20 7 lh.occip.patch.3d lh.occip.patch.flat

MRISread(lh.occip.patch.3d): could not open file

No such file or directory

mris_flatten: could not read surface file lh.occip.patch.3d

No such file or directory