Turns out that Microsoft AutoComplete wasn't registered in the registry, and was causing the dialog box to crash when you try and type.
Runing the following .reg file seems to fix it.
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\CLSID\{00BB2763-6A77-11D0-A535-00C04FD7D062}]
@="Microsoft AutoComplete"
[HKEY_CLASSES_ROOT\CLSID\{00BB2763-6A77-11D0-A535-00C04FD7D062}\InProcServer32]
@=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,6f,00,74,00,25,\
00,5c,00,73,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,00,62,00,72,00,\
6f,00,77,00,73,00,65,00,75,00,69,00,2e,00,64,00,6c,00,6c,00,00,00
"ThreadingModel"="Apartment"
[HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{00BB2763-6A77-11D0-A535-00C04FD7D062}]
@="Microsoft AutoComplete"
[HKEY_CLASSES_ROOT\Wow6432Node\CLSID\{00BB2763-6A77-11D0-A535-00C04FD7D062}\InProcServer32]
@=hex(2):25,00,53,00,79,00,73,00,74,00,65,00,6d,00,52,00,6f,00,6f,00,74,00,25,\
00,5c,00,73,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,00,62,00,72,00,\
6f,00,77,00,73,00,65,00,75,00,69,00,2e,00,64,00,6c,00,6c,00,00,00
"ThreadingModel"="Apartment"