Installing the new 2.5 all inclusive windows version and the configuration fails after the server check.
The error reported is Fatal error: Maximum execution time of 30 seconds exceeded in C:\Moodle25\server\moodle\mod\assign\db\subplugins.php on line 25
Any idea how to troubleshoot this?
First start by describing the whole Moodle environment that you're using. Which "new 2.5 all inclusive windows version" are you using?
Which version of Windows?
Then read http://php.net/manual/en/function.set-time-limit.php and increase the max_execution_time value in your php.ini file.
If you're running IIS then there are some extra settings you can change in FastCGI if the above doesn't solve your problem. I'll describe those once you've confirmed your environment.