When adding several arcs a python exception occurs

An error has occured while executing Python code:

Traceback (most recent call last):
File "C:/Users/Antonio/.qgis2/python/plugins\cadtools\tools\circulararctool.py", line 74, in createCircularArc
self.unsetTool()
File "C:/Users/Antonio/.qgis2/python/plugins\cadtools\tools\circulararctool.py", line 78, in unsetTool
print "****************\* unset tool"
IOError: [Errno 9] Bad file descriptor

Python version:
2.7.5 (default, May 15 2013, 22:44:16) [MSC v.1500 64 bit (AMD64)]

QGIS version:
2.5.0-Master Master, dbed468

Python path: ['C:/OSGEO4~1/apps/qgis-dev/./python/plugins\processing', 'C:/OSGEO4~1/apps/qgis-dev/./python', u'C:/Users/Antonio/.qgis2/python', u'C:/Users/Antonio/.qgis2/python/plugins', 'C:/OSGEO4~1/apps/qgis-dev/./python/plugins', 'C:\OSGEO4~1\bin\python27.zip', 'C:\OSGEO4~1\apps\Python27\DLLs', 'C:\OSGEO4~1\apps\Python27\lib', 'C:\OSGEO4~1\apps\Python27\lib\plat-win', 'C:\OSGEO4~1\apps\Python27\lib\lib-tk', 'C:\OSGEO4~1\bin', 'C:\OSGEO4~1\apps\Python27', 'C:\OSGEO4~1\apps\Python27\lib\site-packages', 'C:\OSGEO4~1\apps\Python27\lib\site-packages\PIL', 'C:\OSGEO4~1\apps\Python27\lib\site-packages\jinja2-2.7.2-py2.7.egg', 'C:\OSGEO4~1\apps\Python27\lib\site-packages\markupsafe-0.23-py2.7-win-amd64.egg', 'C:\OSGEO4~1\apps\Python27\lib\site-packages\pytz-2012j-py2.7.egg', 'C:\OSGEO4~1\apps\Python27\lib\site-packages\win32', 'C:\OSGEO4~1\apps\Python27\lib\site-packages\win32\lib', 'C:\OSGEO4~1\apps\Python27\lib\site-packages\Pythonwin', 'C:\OSGEO4~1\apps\Python27\lib\site-packages\six-1.3.0-py2.7.egg', 'C:\OSGEO4~1\apps\Python27\lib\site-packages\wx-2.8-msw-unicode', 'C:\OSGEO4~1\apps\qgis-dev\python\plugins\fTools\tools', 'C:/Users/Antonio/Google Drive/google-glass-project/AMDB/KMEM/qgs']