Since Google added new features to their reader application it is broken for some users. It stalls at the loading screen with a JavaScript error.

Multiple users reported the problem but were so far ignored by Google. Using different browsers, cleaning the cache even changing computers and networks does not solve the problem.

Logging in with a different account on the very same browser will work just fine. I assume the problems are caused by certain feeds. Unless you are subscribed to a problematic feed, Google reader will continue to work fine.

The JavaScript errors in my case is:

Error: missing } in XML expression
Source file: http://www.google.com/reader/ui/20200667-scroll.js
Line: 543, Column: 23
Source code:
   body {font-family: arial,sans-serif}

others reported similar errors.

References:

http://groups.google.com/group/google-reader-troubleshoot/browse_thread/thread/09e70af6a3c60b89
http://groups.google.com/group/google-reader-troubleshoot/browse_thread/thread/6d003fcea3e349bc

BTW: Looking at the support group, there seem to be serious Opera related problems as well.

I have various issues:

a) Opera – doesn't load since search,
b) IE7 – can't access specific feeds,
c) The tags "advertising" and "microsoft" refuse to load on any browser.

I've had to default back to using Firefox now so that I can access it easily without issue, although my foolish educational establishment (read: sixth form) love Microsoft till the cows come home, so naturally its IE all the way.