Internal Server Error Problem with Orca

I installed the dolphin package including Orca. But when I click the link to orca in Admin to setup orca (under plugins), it shows a page say "Internal Server Error". What have I missed? Ray seems to be working fine.

check server php settings if domxml - xsl are installed.

check also this: http://www.boonex.com/trac/orca/wiki/OrcaDocs