[xwiki-users] (no subject)

Hello XWiki users, being an absolute newbie with XWiki one of the first things after getting somewhat familiar with the concept, I tried to change the skin. I am running on an out-of-the-box installation on MS Windows with HSQLDB and Jetty. I changed it using the Administration link to, for example "finch" skin, but many of the scripts seem to have stopped working afterwards and I get a number of errors like the following when I try to change the skin back to "albatross". 14:58:55,018 ERROR P1-19 http://localhost:8080/xwiki/bin/view/Panels/PanelWizard <http://localhost:8080/xwiki/bin/view/Panels/PanelWizard> ?forceLeftPanels=1&forceRightPanels=1 SimpleLog4JLogSystem:logVelocityMessage:15 4 - Left side ($!hidecolumns) of '==' operation has null value. If a reference, it may not be in the context. Operation not possible. [line 6, column 21] 15:14:17,580 ERROR P1-19 http://localhost:8080/xwiki/bin/view/Main/ <http://localhost:8080/xwiki/bin/view/Main/> SimpleLog4JL ogSystem:logVelocityMessage:154 - VM #breadcrumb: error : too few arguments to m acro. Wanted 3 got 2 15:14:17,580 ERROR P1-19 http://localhost:8080/xwiki/bin/view/Main/ <http://localhost:8080/xwiki/bin/view/Main/> SimpleLog4JL ogSystem:logVelocityMessage:154 - VM error breadcrumb. Null AST 15:14:17,580 ERROR P1-19 http://localhost:8080/xwiki/bin/view/Main/ <http://localhost:8080/xwiki/bin/view/Main/> SimpleLog4JL ogSystem:logVelocityMessage:154 - Left side ($!hidecolumns) of '==' operation ha s null value. If a reference, it may not be in the context. Operation not possib le. [line 6, column 21] 15:15:16,959 ERROR P1-18 http://localhost:8080/xwiki/bin/admin/XWiki/XWikiPrefer <http://localhost:8080/xwiki/bin/admin/XWiki/XWikiPrefer> ences SimpleLog4JLogSystem:logVelocityMessage:154 - Left side ($global) of '!=' operation has null value. Operation not possible. [line 30, column 83] 15:15:16,989 ERROR P1-18 http://localhost:8080/xwiki/bin/admin/XWiki/XWikiPrefer <http://localhost:8080/xwiki/bin/admin/XWiki/XWikiPrefer> ences SimpleLog4JLogSystem:logVelocityMessage:154 - VM #breadcrumb: error : too few arguments to macro. Wanted 3 got 2 15:15:16,999 ERROR P1-18 http://localhost:8080/xwiki/bin/admin/XWiki/XWikiPrefer <http://localhost:8080/xwiki/bin/admin/XWiki/XWikiPrefer> ences SimpleLog4JLogSystem:logVelocityMessage:154 - VM error breadcrumb. Null AST What did I do wrong? Thanks for any help. Wolfgang