Corrupt wp-admin/install.php file…? Please help…

Please can someone help me out here!

When I run the install.php file to install WordPress on my local Apache server the file simply does not run. I have tested everything by changing the install.php file with a simple php test code to bring up my phpinfo(). This runs just fine except when I replace the original WordPress install.php file and I go back to having the same problem.

WordPress 3.0 has had over 4 mil downloads so personally I can’t believe that there will be a problem with this file… but everything else is running smoothly and I have now run out of ideas as to why the wp-admin/install.php file won’t run!!

Please can someone help me with this… I’m loosing my hair here…!