If you are getting a permission error while installing TimeTrex on Windows, or License.php is coming up blank, try the following:
1. Navigate to Start > Programs > Administrative Tools > Internet Information Services (IIS) Manager
2. Expand the tree to where the TimeTrex directory is located. Expand that directory as well.
3. Locate the templates_c directory, right click it, and choose "Permissions."
4. Locate the user: IIS_WPG. On the bottom dialog box (where allow and deny accesses are set), locate the Write permission, and check the "allow" box, do the same for Modify permissions as well. Also locate user: Internet Guest Account, and enable "write" and "modify" permissions using the same method.
5. Press OK to exit that dialog box.
6. Then highlight the "server" that appears on the left side of the Manager. Choose "action" from the menu, ALL Tasks, and then RESTART the IIS Server.
If that fails, you can also take a look at this article on setting proper write permissions.
TimeTrex requires write permissions to its: timetrex/templates_c directory as well as other directories such as its caching and storage directories set in the timetrex.ini.php file.