Try http://pathto/xibo/install/index.php/2 - and if that works you’ve got mod_rewrite problems.
If you are using IIS then the .htaccess file we provide won’t be suitable and you will need to set equivalent rules in your IIS config.
Something like this would be a good start:
<configuration>
<system.webServer>
<rewrite>
<rules>
<rule name="xibo auth" enabled="true">
<match url="api/authorize/.*" />
<action type="Rewrite" url="/api/authorize/index.php" />
</rule>
<rule name="xibo api" enabled="true">
<match url="api/.*" />
<action type="Rewrite" url="/api/index.php" />
</rule>
<rule name="xibo install" enabled="true">
<match url="install/.*" />
<action type="Rewrite" url="/install/index.php" />
</rule>
<rule name="xibo maint" enabled="true">
<match url="maint/.*" />
<action type="Rewrite" url="maint/index.php" />
</rule>
<rule name="xibo web" enabled="true">
<match url=".*" />
<action type="Rewrite" url="/index.php" />
</rule>
</rules>
</rewrite>
</system.webServer>
^^ that is a guess based on some googling