I was working through Christian Schneider's Karaf tutorial #3 (http://www.liquid-reality.de/display/liquid/2011/09/26/Karaf+Tutorial+Part+3+-+Improving+configuration+editing+using+the+OSGI+Metatype+Service+and+the+Felix+Webconsole). After presenting my findings to Christian, he believes this is a bug in the webconsole for this version of Karaf, and asked me if I could open an issue here.
The problem is that after building his ConfigAdmin project & installing in Karaf, if you attempt to edit that project's configuration (ConfigApp.cfg) file through the webconsole, the following error is raised:
The request failed:
If I uninstall the configapp & configapp-blueprint features, I can then edit the remaining ConfigApp.cfg file through the webconsole, receiving the message that the form was automatically generated because no property descriptors are available (which makes sense because I uninstalled the associated features).
His tutorial references Karaf 2.2.4 which did not have this problem, and he has tested in 3.0.0.RC1 without seeing this problem. 2.3.1 however seems to have this issue.