XCode crashes on startup

When I startup Xcode I get the following error:

The application Xcode quite unexpectedly. Clicking on the Report... button gives the following:

Process:         Xcode [875]
Path:            /Developer/Applications/Xcode.app/Contents/MacOS/Xcode
Identifier:      com.apple.Xcode
Version:         ??? (???)
Build Info:      DevToolsIDE-9210000~1
Code Type:       X86 (Native)
Parent Process:  launchd [140]

Date/Time:       2009-03-12 15:13:14.839 -0500
OS Version:      Mac OS X 10.5.6 (9G55)
Report Version:  6

Exception Type:  EXC_BAD_INSTRUCTION (SIGILL)
Exception Codes: 0x0000000000000001, 0x0000000000000000
Crashed Thread:  0

Application Specific Information:
objc[875]: '/System/Library/PrivateFrameworks/DebugSymbols.framework/Versions/A/DebugSymbols' was not compiled with -fobjc-gc or -fobjc-gc-only, but the application requires GC
objc[875]: *** GC capability of application and some libraries did not match
...

The full detail can be seen here. I've never used Xcode before (although I did run it when I first installed it). Any ideas on what could be causing this?

From stackoverflow

• Download and install the latest version of Xcode. That's what I did to fix this issue.

• If you just installed safari 4, either revert back to 3 or install the latest version of Xcode. Hope that helps

  Abdullah Jibaly : Yes, I did install Safari 4... Any help on installing the lastest version of Xcode (I already ran System Update)?

  Ben Reeves : http://developer.apple.com/technology/Xcode.html

  Abdullah Jibaly : Got it, Apple Dev Connection. Thanks!

  Robert S. : @Abdullah, this is precisely the situation I was in. :)

  mt3 : uninstalling safari 4 beta does not eliminate the problem; you must upgrade xcode