I only tried it with Opera, but I reviewed the source code and there is no indication it tries to handle these cases:
1) Session expired.
You want to download the following file:
http://rapidshare.com/files/xxxxxxx/somefile.rar | xxxxxx KB
The download session has expired. Please click here to start the download again.
2) NW congested
Currently a lot of users are downloading files. Please try again in 2 minutes or become a Premium member