Windows – Multiple paths in php.ini open_basedir on Windows

I'm attempting to use multiple paths for my php open_basedir config value, in php.ini on a windows server.

The line I'm using is:

open_basedir = E:/Websites;C:/PHP/includes/

Unfortunately, it's ignoring the second entry. Whenever I try to execute code in the C:/PHP/includes directory (this example happens to be PHPUnit), I get

PHP Warning: require(): open_basedir restriction in effect. File(C:\PHP\includes\PHPUnit\PHPUnit-3.6.10\PHPUnit\Autoload.php) is not within the allowed path(s) : (E:/Websites) in C:\PHP\includes\PHPUnit\PHPUnit-3.6.10\phpunit.php on line 41

Note, it's not even showing the second item in the paths list. Can anyone spot where I'm going wrong?

Am I right in thinking that semicolon (;) denotes a comment? If so, how do I separate the entries, as the manual doesn't make it clear