For some reason when I try to run a program there are errors and iPhone simulator won't come up. It says:

Interface Builder encountered an error communicating with the iPhone Simulator. Failed to determine the value for systemColors of UIColor.

Command/Developer/usr/bin/ibtool failed with exit code 1

... if anyone can give me any help it would be much appreciated! If you need for information I'll be glad to provide it.

Now I tried to download Xcode 4, and it won't even open, When I try to open it it says:

Xcode encountered an internal logic error. Choose "Continue" to continue running Xcode in an inconsistent state. Choose "Crash" to halt Xcode and file a bug with Crash Reporter. Choosing "Crash" will result in the loss of all unsaved data.

Show Details:

UNCAUGHT EXCEPTION (NSInternalInconsistencyException): Couldn't load plug-in '' while firing fault for extension 'Xcode.Device.iPhonePlaceholder'
UserInfo: {
NSUnderlyingError = "Error Domain=DVTPlugInErrorDomain Code=2 \"Loading a plug-in failed.\" UserInfo=0x4001cc760 {, DVTPlugInExecutablePathErrorKey=/Developer/Platforms/iPhoneOS.platform/Develope r/Library/Xcode/PrivatePlugIns/IDEiPhoneSupport.ideplugin/Contents/MacOS/IDEiPho neSupport, NSLocalizedRecoverySuggestion=The plug-in or one of its prerequisite plug-ins may be missing or damaged and may need to be reinstalled., NSLocalizedDescription=Loading a plug-in failed., NSFilePath=/Developer/Platforms/iPhoneOS.platform/Developer/Library/Xcode/Priva tePlugIns/IDEiPhoneSupport.ideplugin, NSLocalizedFailureReason=The plug-in \\U201d at path \U201c/Developer/Platforms/iPhoneOS.platform/Developer/Library/Xcode/PrivatePlu gIns/IDEiPhoneSupport.ideplugin\U201d could not be loaded. The plug-in or one of its prerequisite plug-ins may be missing or damaged., NSUnderlyingError=0x400354580 \"The bundle \U201cIDEiPhoneSupport\U201d couldn\U2019t be loaded because it is damaged or missing necessary resources.\"}";
Hints: None
0 0x00007fff8e64326a __exceptionPreprocess (in CoreFoundation)
1 0x00007fff88122d5e objc_exception_throw (in libobjc.A.dylib)
2 0x000000010cdfb4e0 -[DVTExtension _fireExtensionFault] (in DVTFoundation)
3 0x000000010cde5786 __38-[DVTDispatchLock performLockedBlock:]_block_invoke_0 (in DVTFoundation)
4 0x00007fff8b678aad _dispatch_barrier_sync_f_invoke (in libdispatch.dylib)
5 0x000000010cde572f -[DVTDispatchLock performLockedBlock:] (in DVTFoundation)
6 0x000000010cdfb27b -[DVTExtension _valueForKey:inParameterData:usingSchema:] (in DVTFoundation)
7 0x000000010cdfb1bf -[DVTExtension valueForKey:] (in DVTFoundation)
8 0x000000010cdfa997 +[DVTDevice _knownDeviceLocators] (in DVTFoundation)
9 0x000000010cdfa4f0 -[DVTDeviceManager startLocating] (in DVTFoundation)
10 0x000000010d352cfc IDEInitialize (in IDEFoundation)
11 0x000000010d6d3c18 -[IDEApplicationController applicationWillFinishLaunching:] (in IDEKit)
12 0x00007fff8928bde2 __-[NSNotificationCenter addObserver:selector:name:object:]_block_invoke_1 (in Foundation)
13 0x00007fff8e5ebe0a _CFXNotificationPost (in CoreFoundation)
14 0x00007fff89278097 -[NSNotificationCenter postNotificationName:object:userInfo:] (in Foundation)
15 0x00007fff8a899922 -[NSApplication finishLaunching] (in AppKit)
16 0x00007fff8a8994d4 -[NSApplication run] (in AppKit)
17 0x00007fff8ab1880c NSApplicationMain (in AppKit)
18 0x000000010cddeeec (in Xcode)
19 0x0000000000000002

Could someone tell me how to delete this thread or just delete it for me?