I create imagemosaic with many big pictures, but in geoexplorer or geowebcache this layer is not display. If i create imagemosaic with 3(for example) pictures(from big imagemosaic) then layer display, why?
the base error seems to be:
which would only occur if you had lost a geotools jar out of the WEB-INF directory or you have mixed two different versions together.
Are you sure you fetched the version of the plugin that matches your geoserver version?