I got the same error after I upgraded from ZF 1.8.0 to 1.8.4, after searching for a solution with no luck I posted my error on the ZF Gdata mail list and Trevor Johns was nice enough to get back to me with this response:
"This looks like this issue:
http://framework.zend.com/issues/browse/ZF-7013
This will be fixed in the next release of Zend Framework. If you don't
want to wait that long, you can either:
- Download a development snapshot from here:
hxxp://framework.zend.com/code/browse/~tarball=zip/Zend_Framework/standard/trunk/trunk.zip
- Use version 1.8.3:
hxxp://framework.zend.com/releases/ZendFramework-1.8.3/ZendFramework-1.8.3.tar.gz
- Don't use Zend_Loader's autoloader functionality. (This bug only
seems to show up if you're trying to autoload the classes.)"
I'll be rolling back my ZF version until the next release.
p.s. had to substitute http with hxxp because "new users can only post a maximum of one hyperlink" apparently.