Code:
C:\Program Files (x86)\Calibre2\DLLs\python26.dll
I hope the (x86) was supplied by the debugger because that part of the with a leading space, does not exist on XP versions (is this a 64 bit thing?)
6.40 is out and I have not seen a crash of python26.dll in days
Kovid thinks he found something and fixed it

in this version.