open: No such file or directory

What steps will reproduce the problem?
import pysam

pysam.sort(IdoNOTexist.bam)
pysam.fixmate(IdoNOTexist.bam)
pysam.faidx(IdoNOTexist.bam)

What is the expected output? 
I would expect to get a feedback whether the command was successful executed 
and to see something like in pysam.index:
Traceback (most recent call last):
  File "p2.py", line 6, in <module>
    pysam.index('ab.sorted.bam')
  File "/lib/python2.7/site-packages/pysam-0.6-py2.7-linux-x86_64.egg/pysam/__init__.py", line 50, in __call__
    retval, stderr, stdout = csamtools._samtools_dispatch( self.dispatch, args )
  File "csamtools.pyx", line 2850, in csamtools._samtools_dispatch (pysam/csamtools.c:25974)
IOError: No such file or directory: 'ab.sorted.bam'

What do you see instead?
pysam.sort
open: No such file or directory

pysam.fixmate
open: No such file or directory
Segmentation fault

pysam.faidx
open: No such file or directory
[]

What version of the product are you using? On what operating system?
pysam 0.6 with 64 bit ubuntu

Original issue reported on code.google.com by mictadlo on 29 Feb 2012 at 10:33

lixin6135 / pysam

open: No such file or directory #89