Add this:
// List of allowed file types
// Pay attention to the "Last Message:" in the status bar if your file is being rejected
// because of its file type. It should display the proper MIME type there, and you can
// then add that string to this list to allow it
$GLOBALS['allowedFileTypes'] = array('image/gif', 'text/html', 'text/plain', 'application/pdf', 'application/x-pdf', 'application/x-lyx', 'application/msword', 'image/jpeg', 'image/pjpeg', 'image/png', 'application/msexcel', 'application/msaccess', 'text/richtxt', 'application/mspowerpoint', 'application/octet-stream', 'application/x-zip-compressed','image/tiff','image/tif','application/vnd.ms-powerpoint');
To add a new filetype, check the error in the status bar of opendocman when you try to upload the exe, and copy the filetype info from the message, and place it at the end of the config line above in your config_local.php
I'm trying to do something similar but with odt (Open office) files. I tried text/odt and that didn't work. I couldn't find anywhere where the file type was listed.
when the upload fails, you should see a message in the blue bar, on the right side of it. The message should show you what mime-type failed. That will be the mime-type to add.