Error Clodius aggregate: RuntimeError: Invalid interval bounds!

Hi ,
I am trying to aggregate a bigWig and clodius send me the following error:
```
position: 167772161 progress: 0.05 elapsed: 106.55 remaining: 1885.81
len(data_buffers[curr_zoom]) 16777216
positions[curr_zoom]: 167772160
Traceback (most recent call last):
File "/home/samuel/programs/bin/clodius", line 11, in
load_entry_point('clodius==0.7.0', 'console_scripts', 'clodius')()
File "/usr/local/src/anaconda2/lib/python2.7/site-packages/click/core.py", line 722, in __call__
return self.main(*args, **kwargs)
File "/usr/local/src/anaconda2/lib/python2.7/site-packages/click/core.py", line 697, in main
rv = self.invoke(ctx)
File "/usr/local/src/anaconda2/lib/python2.7/site-packages/click/core.py", line 1066, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "/usr/local/src/anaconda2/lib/python2.7/site-packages/click/core.py", line 1066, in invoke
return _process_result(sub_ctx.command.invoke(sub_ctx))
File "/usr/local/src/anaconda2/lib/python2.7/site-packages/click/core.py", line 895, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/usr/local/src/anaconda2/lib/python2.7/site-packages/click/core.py", line 535, in invoke
return callback(*args, **kwargs)
File "build/bdist.linux-x86_64/egg/clodius/cli/aggregate.py", line 1104, in bigwig
File "build/bdist.linux-x86_64/egg/clodius/cli/aggregate.py", line 669, in _bigwig
RuntimeError: Invalid interval bounds!
```
(he is still on chr1).
Do you have any idea what it could be? My bigwig seems fine with other programs...
Thanks!