This package only applies to Umbraco 4.7.0! It is not intended to support any previous or future versions. As of Umbraco 4.7.1 the back-office timeout has been configurable via a new setting in umbracoSettings.config called /settings/security/keepUserLoggedIn which should be set to false.
Getting tired of timeouts in the Umbraco back-office? Sick of the login overlay prompt? Wish it would just disappear whilst you are developing your website?
There is a solution... The Disable BackOffice Timeout package!
Simply install the package, set the "umbracoDisableTimeout" AppSettings key in your Web.config and... Ta-dah! No more login prompts!
The intention of this package is that it should only be used in a development environment, not a production environment (by real content editors, etc).
So... what does the package actually do?
This results in disabling any calls to the "GetSecondsBeforeUserLogout" web-service - which would usually log you out after the set inactivity period.
Uninstalling the package will remove both the HttpModule and AppSettings key, reverting your Umbraco install back to normal.
With thanks to Matt Brailsford.