What steps will reproduce the problem?
1. fetch last.fm scrobbles
2. choose itunes
3. will not update itunes

What is the expected output? What do you see instead?
expect it to continue

What version of the product are you using? On what operating system?
itunes 10.1.0.54

Please provide any additional information below.
my last.fm username is rdu90 and i am using version 2.1 of scrobblemapper onw 
windows7

Some users reported errors where the Last.fm server returned invalid XML markup 
when invoked, and the application doesn't know how to escape it or compensate 
for it.

This would be a problem on lastfm's side usually, but they don't seem to be 
able to (or keen to) fix it any time soon.

Fixing it will be troublesome because I use automatic deserialization in WCF 
and there doesn't seem to be anywhere I can intercept the stream to patch it.

See : http://www.last.fm/group/Last.fm+Web+Services/forum/21604/_/621372

Some users reported that as low as 50% of scrobbles were downloaded from 
last.fm, or matched. This may be a problem with the download process, threading 
or just misinterpretation of date values.

No use downloading everything everytime, if there's a local store, the app 
could download only the latest scrobbles and thus make the updates much faster.

It would be nice if there was an option to export the whole list of scrobbles 
to an xml, csv or xls file.

The concurrency framework used in this project (Parallel Extensions for .NET) 
is discontinued and unsupported, it also has known bugs and shortcomings. All 
of these would be fixed if the project were upgraded to 4.0 and used the new 
concurrency primitives.