[Tutor] How to examine the following problem

[lina]

Hi,

I meet a problem, mainly some error waring:

CmdException Exception in Tk callback
   Function: <function <lambda> at 0x46fdde8> (type: <type 'function'>)
   Args: ()
Traceback (innermost last):
   File "/usr/lib/python2.7/dist-packages/Pmw/Pmw_1_3/lib/PmwBase.py", 
line 1747, in __call__
     return apply(self.func, args)
   File "/usr/lib/python2.7/dist-packages/Pmw/Pmw_1_3/lib/PmwDialog.py", 
line 153, in <lambda>
     command=lambda self=self, name=name: self._doCommand(name))
   File "/usr/lib/python2.7/dist-packages/Pmw/Pmw_1_3/lib/PmwDialog.py", 
line 132, in _doCommand
     return command(name)
   File "/usr/local/bin/modules/pmg_tk/startup/dssp_stride_pymol.py", 
line 864, in execute
     rtn = self.runDSSP()
   File "/usr/local/bin/modules/pmg_tk/startup/dssp_stride_pymol.py", 
line 533, in runDSSP
     sse_sel_name = self.selectSSE(sse)
   File "/usr/local/bin/modules/pmg_tk/startup/dssp_stride_pymol.py", 
line 719, in selectSSE
     cmd.select(sel_name_chn, sel_expr)
   File "/usr/local/bin/modules/pymol/selecting.py", line 118, in select
     if _self._raising(r,_self): raise pymol.CmdException
CmdException: <pymol.CmdException instance at 0x47f8830>

The code I was downloading from
http://www.biotec.tu-dresden.de/~hongboz/dssp_pymol/pymol_script/dssp_stride_pymol.py

I am not experienced to fix it.

Thanks ahead for your suggestions about how to solve this problem.
 From where to examine.

Best regards,