I found a problem that appeared in the latest version of Geoserver... and wasn't present in the beta.
Description of the situation:
In my PostGIS database, I have table names with both lower case and upper case characters.
Case 1)
When I try to add a lower case named table in Geoserver, everything works fine (in every situation).
Case 2)
When I try to add a table with both lower case and upper case characters.. in Geoserver, it also works fine.
Case 3)
If there's a primary key defined in my table... Things go wrong. When Geoserver detects a primary key, it converts the name of the selected table with only lower case characters!... So if the real name in my PostGIS database doesn't match the lower cased version, Geoserver prints a beautifull "Error 500" message because it doesn't find it.
Nicolas Vila