simplepie problems

After the upgrade to 2.8.2 every now and then, in my dashboard I get: Your feed at is empty. on top of my Dashboard and sometimes the feed doesn't display in the dashboard.

Loking at my error log I found this:

[Sat Jul 25 20:54:04 2009] [warn] mod_fcgid: stderr: PHP Notice: XML error: Reserved XML Name at line 4, column 38 in /var/www/clients/clientx/webx/web/wp-includes/class-simplepie.php on line 1791

Googling showed some people having the same problem but their error was to insert whitespace in i.e. wp-config.php which I already checked and mine is fine.

How can I go about and analyze what is happening here?

I analyzed the above feed and this one here: as I am not sure which one of them is causing the problem but they both are fine except for a warning...