iCAL and lost calendars

Hello,
after a syncronization with mobileme, my iCAL program seems to be dead. No calendars opened in the left column, no way to create another one or to import from other sources. In other words it's dead. Any suggestions? To reinstall iCAL have I to use the OSx Leopard disc?
Any help will be welcome
Thanks

You can use OSx Leopard Disk 1 to selectively install basic apps like iCal, iChat and iMail, etc. I have the same problem, although I'm not sure what precipitated the problem. I switched from PC to Mac year and a half ago and did things like I use to do them in Windows, such as the user name for the sign-on. I even use Disk Utility to fix file permissions, but to no avail! Let us know your results.