I am unable to log-in to Ubuntu with the username/password combination I gave on Wubi at the time of installation (incorrect username/password error). This happened twice; the first time I really thought I forgot the password and/or the username and ran Wubi again but it happened the second time too. Guest access works fine, and strangely while the Wubi installer says I'm about to install 12.04, it actually ends up downloading and installing 13.04. Any ideas would be appreciated.
There is a bug that Wubi will install the dev release (13.04) if you are using an out of date installer e.g. for 12.04 or 12.04.1. The current Wubi for 12.04 is 12.04.2 and you need this latest version for it to work.
Some reports of it happening on the 12.10 version of Wubi.exe have not been confirmed. If yours was 12.10, please pastebin the Wubi log file (find it in the
%TEMP% directory calle
wubi-nn.nn-revxxx.log) so we can add it to the relevant bug report.
Note that the development release for Wubi is broken. Therefore there is nothing you can do with it and you should uninstall it and reinstall using a current and supported release such as 12.04.2 or 12.10. Both are available from http://www.ubuntu.com/download/desktop/windows-installer
For reference, here are the bug reports: