error when shape clustering

[Jing JC]

[root@centos57 AdaleMono]# shapeclustering -F font_properties -U unicharset eng.matrx60x40.exp0.tr

Reading eng.matrx60x40.exp0.tr ...

Error: Unable to open eng.matrx60x40.exp0.tr!

signal_termination_handler:Error:Signal_termination_handler called:Code 3000

Segmentation fault

(snaplocaldev)[root@centos57 AdaleMono]# mftraining -F font_properties -U unicharset -O eng.unicharset eng.matrx60x40.exp0.box.tr

Warning: No shape table file present: shapetable

Reading eng.matrx60x40.exp0.box.tr ...

*** glibc detected *** mftraining: munmap_chunk(): invalid pointer: 0x09179128 ***

======= Backtrace: =========

/lib/libc.so.6(cfree+0x188)[0x622d88]

/usr/lib/libstdc++.so.6(_ZdlPv+0x21)[0x635b5c1]

/usr/lib/libstdc++.so.6(_ZdaPv+0x1d)[0x635b61d]

mftraining(_ZN13GenericVectorIiE5clearEv+0x4e)[0x804d25e]

[Jing JC]

I followed the naming convention though:

tesseract [lang].[fontname].exp[num].tif [lang].[fontname].exp[num] nobatch box.train

while my font name contained number: 

my font name is matrx60x40, 

I changed to the name arial,and it worked. 

weird. 

I tried replacing the font name to matrx60x40 again, 

that's the only difference. and not working again. 

Why is that?