install ec-fonts-mftraced-1.0.8 error

[Julie Gong]

Thank you very much for developing lily pond.

When I install ec-fonts-mfraced-1.0.8, I got the following error:
(/usr/share/texmf/fonts/source/jknappen/ec/exrligtb.mf
Ok) ) ) )
Font metrics written on ecbx10.tfm.
Output written on ecbx10.7227gf (256 characters, 1015780 bytes).
Transcript written on ecbx10.log.


Tracing bitmaps... Invoking `gf2pbm -n 0 -o char.pbm ecbx10.7227gf'

Opening pipe `gf2pbm -n 0 -s ecbx10.7227gf'
Traceback (most recent call last):
 File "/usr/local/bin/mftrace", line 1208, in ?
   magnification)
 File "/usr/local/bin/mftrace", line 635, in trace_font
   success = trace_one ("char.pbm", '%s-%d' % (gf_fontname, a))
 File "/usr/local/bin/mftrace", line 348, in trace_one
   status = system (trace_command (pbmfile, ''), 1)
TypeError: 'NoneType' object is not callable
make: *** [pfa/ecbx10.pfa] Error 1
I use Redhat linux 8.0. Please help !! Thank you again.

Julie