Jcal Pro is the worst calendar component we've ever worked with. It is not only buggy and doesn't work as expected, but we've found out that it can be hacked as well.  Just do a search on Google, you'll find it.

After installing, the wrong dates show up, we get "access denied" errors, and other buggy problems.  The developers are no help either.  The worst thing is that it's not free, they actually charge you for all these problems. Go check thier forum and you will find an enourmous amount of user problems with Jcal Pro.

Do yourself a favor and stay far away form Jcal Pro, unless you want to get your website hacked.   Try Jevents instead.