I suppose that the problem would be that there is already a 'TCalendar' component in the misc pallette,so when I try to install the calendar component onto this pallette,the compiler gives 'illegal unit name' error.and I remember someone had said that one should not compile the zcomponent package,just install it after the compilation of the zcore,zparsesql,zplain and zdbc package.How ever, there are still problems:when I install the zcomponent package without compiling it,there comes much compiler error like 'fatal:can't find unit xxx',thouth I had set the unit path in the menu:project->compiler options->other unit files,and the menu:open recent packages->zcomponent.lpk->compiler options->other unit files,sometimes this is ok,but sometimes it does not work.For example: when I see the 'fatal:can't find unit xxx',I check that it is really in the unit path(such as 'e:\lazarus\lcl\xxx.pp'),but the compiler still complains 'can't find unit',and I was confused,it is very strange.