ps2raster error abot Chinese characters

Dear GMT users,
    
When I convert the PS format figure containing Chinese characters to other format like PNG or TIF, there is a error:

Error: /invalidfileaccess in /findfont
Operand stack:
   167   STSong-Light--GB-EUC-H
Execution stack:
   %interp_exit   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   --nostringval--   --nostringval--   false   1   %stopped_push   1932   1   3   %oparray_pop   1931   1   3   %oparray_pop   1915   1   3   %oparray_pop   1803   1   3   %oparray_pop   --nostringval--   %errorexec_pop   .runexec2   --nostringval--   --nostringval--   --nostringval--   2   %stopped_push   --nostringval--   --nostringval--   1884   2   4   %oparray_pop
Dictionary stack:
   --dict:1170/1684(ro)(G)--   --dict:0/20(G)--   --dict:77/200(L)--   --dict:148/250(L)--
Current allocation mode is local
Current file position is 17236

It implys that this error is related to 'STSong-Light--GB-EUC-H' which is a kind of Chinese font. But I have no idea how to fix it.
Would anyone please give some help?

PS: I use Window 7+GMT5.1.0

Lei Yang
2014-03-26