This is actually a python-tk bug. Fix it here, though...

#395867: python-tk breaks with LC_NUMERIC != C
#395892: pycocuma doesn't work with python-pmw built for python2.4

--- pycocuma-0.4.5-6.orig/pycocumalib/MainController.py
+++ pycocuma-0.4.5-6/pycocumalib/MainController.py
@@ -66,6 +66,7 @@
             self.splash.show()
         import locale    
         locale.setlocale(locale.LC_ALL, '')
+        locale.setlocale(locale.LC_NUMERIC, 'C')
         self.model = MainModel()
         if not self.nogui:
             tkroot = None