[brownam]

I've been using prevoius versions of Calibre with no problem. I have
Windows Vista Help Premium Service Pack 1. I upgrade to V0.4.112. I've
gone back to previous version that did work (4.86) and that now fails too.

After reading the FAQ I:
Deleted _python* and lib*.db1
Delete the Calibre dir
Deleted Books dir
Deleted any keys in RegEdit32
and re-installed still fails to start.

The Debug comes up with
c:\Program Files\calibre>.\calibre-debug -c "from calibre.gui2.main import main;
main()"
Traceback (most recent call last):
File "debug.py", line 96, in <module>
File "debug.py", line 80, in main
File "<string>", line 1, in <module>
File "c:\Program Files\calibre\library.zip\calibre\gui2\main.py", line 1423, i
n main
File "c:\Program Files\calibre\library.zip\calibre\gui2\main.py", line 74, in
__init__
File "calibre\gui2\main_ui.pyo", line 143, in setupUi
File "calibre\gui2\library.pyo", line 547, in __init__
File "calibre\gui2\library.pyo", line 115, in __init__
File "calibre\utils\config.pyo", line 452, in __getitem__
File "calibre\utils\config.pyo", line 459, in get
File "calibre\utils\config.pyo", line 449, in refresh
File "calibre\utils\config.pyo", line 388, in parse
File "calibre\utils\config.pyo", line 310, in parse_string
TypeError: expected string without null bytes