Thanks for the hint! That was contextmenu plugin. But it's one of the 'built-in' plugins, coming with RC.
And it is the same on both servers. Version "2010 10 05", that's the last entry in CHANGELOG. No newer version in git.
Should I report this as a bug? Or it's Ubuntu related?
BR,
Ivars

On 2011.05.12. 12:53, A.L.E.C wrote:

On 12.05.2011 10:58, Ivars Strazdiņš wrote:

[2011.05.12. 11:50:48] JavaScript -
https://myhost.my.domain/?_task=addressbook
Event thread: DOMContentLoaded
Uncaught exception: Syntax error, unrecognized expression:
[id=rcmrowZGM9c2V0cyxkYz1sdg==]

Disable all plugins and check again.