2.2 RC1 manager UI crashes after sucessful instalation

after sucessfull instalation in subfolder 'modx' while trying to open backend i see blank page and following message in error log:
[Tue Nov 22 12:11:43 2011] [error] PHP Fatal error: Class 'modX' not found in /home/xxxxx/sitename/www/modx/core/model/modx/modmanagercontroller.class.php on line 910

but frontend works fine and generate default content normally

then i trying install revo 2.2 on localhost in WAMP 2.2. and have not problem )
so, this is "floating" troble [ed. note: digdream2012 last edited this post 12 years, 5 months ago.]

Try to reupload the files inside the core folder, some times it doesn't copy all files good. Not sure where this comes from, but I also get it some times.

I would also upload the manager and connectors folders.

It also works much better if you zip up the files and then unzip them on the remote server rather than using FTP. It's common for files to be missing or corrupted in an FTP transfer.

reuploading does not help.
analyzing index.php in manager folder i found place where script crashes

if (isset($modx) && is_object($modx) && $modx instanceof modX) {
    if (!$modx->getRequest()) {
        $modx->log(modX::LOG_LEVEL_FATAL,"Could not load the MODX manager request object.");
    }
    if (!MODX_API_MODE) {
// before this line all works fine
        $modx->request->handleRequest();
// after - script stop running
    }
}
@session_write_close();
exit();

at last i try nightly 2.2 - seems same problem
and 2.1.5 stable - all works correctly