It could be one of 2 things...
1.) You did not setup the global.php file correctly for the Admin2 directory, therefore not allowing the other files to work (as they require it)...Make sure you followed the instructions carefully

2.) Sometimes, and I know this is true, some files dont like being uploaded in Ascii Mode...On my server, I have to upload all vBulletin files in BINARY mode, so that they will work...Make sure you are uploading in the BINARY mode...If you are not sure which mode you are uploading in, try downloading
SmartFTP, which has the option for Ascii and Binary modes when uploading...It will be on the top Quick Toolbar, and by default is Auto...Change it to Binary or Ascii, and upload...If that mode does not work, try the other...
Thats all I can suggest thats wrong...If it still does not work, email your new global.php file to me at :
hellsatan@darkblazes.com
Satan