iOS interface Builder error in xcode

Hi All
I have problem with interface builder. so
environment: mac os 10.5.6 .sdk 2.2.
I create new empty project select the project type (iPhone OS->application) then select view based application build project and everything is good
But when I try open my window.xib file (double click on this file) a get error for my interface builder it cant start and open this file.
What`s wrong ?
How I can solve this problem
Thanks

dejo said:

Can you start Interface Builder on its own? It's usually found in /Developer/Applications. If not, and you get the same error, you may need to reinstall the SDK. What is the error you are getting, by the way?

Click to expand...

Hi
No I can not start form application folder too.
I got such error message.

The application Interface Builder quite unexpecdly
Mac OS X and other application

Click to expand...

Report
Process:Interface Builder
Version 3.1.2

Exeption type EXC_BAD_ACCESS(SIGBUS)
EXEC CODE:KERN_PROTECTEDFAILUAR

i have one more question
i must uninstall and install again or i can reinstall without uninstalling
Thanks

dejo said:

To be safe, it's best to uninstall first. Also, you might want to consider redownloading the SDK, since yours may have been corrupted.

Click to expand...

thanks I will try
one more question too
how can you explain me how can I uninstall the sdk i am a beginner in mac can you explain what i must do
I read the manual for uninstall sdk and found such string "sudo /Developer/Library/uninstall-devtools --mode=all" how I can run this line?
I have iphone_sdk_for_iphone_os_2.1__final which version you are recommended for installation?
Thanks