iChat doesn't launch

Starting yesterday, iChat will crash before launching. It gives me this error:

Process: iChat 178
Path: /Applications/iChat.app/Contents/MacOS/iChat
Identifier: com.apple.iChat
Version: ??? (???)
Build Info: iChat-6040000~2
Code Type: X86 (Native)
Parent Process: launchd 91

Date/Time: 2008-03-26 14:13:14.393 -0400
OS Version: Mac OS X 10.5.2 (9C31)
Report Version: 6

Exception Type: EXC_BREAKPOINT (SIGTRAP)
Exception Codes: 0x0000000000000002, 0x0000000000000000
Crashed Thread: 0

Dyld Error Message:
Library not loaded: /System/Library/PrivateFrameworks/VideoConference.framework/Versions/A/VideoConference
Referenced from: /Applications/iChat.app/Contents/MacOS/iChat
Reason: no suitable image found. Did find:
/System/Library/PrivateFrameworks/VideoConference.framework/Versions/A/VideoConference: stat() failed with errno=5


I have never had this problem before. I have restarted my laptop, but don't know what else to do. Problem persists.

Help please?
Dreier Carr

Mac Book Pro Mac OS X (10.5.2) iChat 4.0.2