Just opened Reaper 4.11 (went back to this after 4.151 was un-useable on OS X for me)
Openend Nexus 1 as I normally do and CRASH :
Process: REAPER [591]
Path: /Applications/REAPER.app/Contents/MacOS/REAPER
Identifier: com.cockos.reaper
Version: ??? (4.11)
Code Type: X86 (Native)
Parent Process: launchd [285]
Date/Time: 2012-02-28 10:43:58.715 +0000
OS Version: Mac OS X 10.7.2 (11C74)
Report Version: 9
Interval Since Last Report: 522495 sec
Crashes Since Last Report: 1
Per-App Interval Since Last Report: 326407 sec
Per-App Crashes Since Last Report: 1
Anonymous UUID: 8A018342-778C-4D04-A696-CE20DB35A5A8
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x00000000cc206ae8
VM Regions Near 0xcc206ae8:
CG backing stores 00000000cbb4f000-00000000cbe4f000 [ 3072K] rw-/rw- SM=SHM
-->
Submap 00000000ffff0000-00000000ffff2000 r-x/r-x process-only submap
Application Specific Information:
objc[591]: garbage collection is OFF
Performing @selector(onSwellCommand
from sender REAPERSwell_button 0x97c480
Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 com.reFX.Nexus 0x11ba5fa1 0x11b93000 + 77729
1 com.reFX.Nexus 0x11bab6b0 0x11b93000 + 100016
2 com.reFX.Nexus 0x11c38d81 VSTPluginMain + 465421
3 com.reFX.Nexus 0x11bab467 0x11b93000 + 99431
4 com.reFX.Nexus 0x11bc50be AUVSTViewEntry + 50542
5 com.reFX.Nexus 0x11bc6b8c AUVSTViewEntry + 57404
6 com.reFX.Nexus 0x11bb8970 AUVSTEntry + 3426
7 com.reFX.Nexus 0x11bb1bd8 0x11b93000 + 125912
8 com.reFX.Nexus 0x11bb21fa 0x11b93000 + 127482
9 com.reFX.Nexus 0x11bb8b77 AUVSTViewEntry + 39
10 com.apple.CoreServices.CarbonCore 0x97cb75f5 CallComponent + 223
11 com.apple.CoreServices.CarbonCore 0x97cb763e CallComponentDispatch + 29
12 com.apple.audio.toolbox.AudioToolbox 0x97be6fb7 _AT_AudioUnitCarbonViewCreate + 73
13 com.cockos.reaper 0x0035bf71 AU_Plugin::ShowConfig(HWND__*, RECT*) + 1217
14 com.cockos.reaper 0x00227a2c _ZN5FxDsp10showConfigEP6HWND__P4RECTi. + 347
15 com.cockos.reaper 0x0024b0c9 _ZN7FxChain16displayDspConfigEP6HWND__i. + 312
16 com.cockos.reaper 0x00242d18 FxChain::dialogProc(HWND__*, unsigned int, unsigned long, long) + 20584
17 com.cockos.reaper 0x0023dc69 FxChain::staticDialogProc(HWND__*, unsigned int, unsigned long, long) + 73
18 com.cockos.reaper 0x0032b87e -[REAPERSwell_hwnd initChild:Parent:dlgProc:Param:] + 654
19 com.cockos.reaper 0x00331a7f -[REAPERSwell_modelesswindow initModeless:Parent:dlgProc:Param
utputHwnd:] + 559
20 com.cockos.reaper 0x0032f8ac SWELL_CreateDialog(SWELL_DialogResourceIndex*, char const*, HWND__*, long (*)(HWND__*, unsigned int, unsigned long, long), long) + 332
21 com.cockos.reaper 0x00248404 _ZN7FxChain10showDialogEbb. + 161
22 com.cockos.reaper 0x0015507c MediaTrack::ShowFxWindow(bool, bool, bool) + 124
23 com.cockos.reaper 0x00262fc6 addDialogProc(HWND__*, unsigned int, unsigned long, long) + 13270
24 com.cockos.reaper 0x00331e0a SwellDialogDefaultWindowProc(HWND__*, unsigned int, unsigned long, long) + 74
25 com.cockos.reaper 0x0032ad84 -[REAPERSwell_hwnd onSwellCommand:] + 356
26 com.apple.CoreFoundation 0x9be79091 -[NSObject performSelector:withObject:] + 65
27 com.apple.AppKit 0x9572ecb3 -[NSApplication sendAction:to:from:] + 232
28 com.apple.AppKit 0x9572eb90 -[NSControl sendAction:to:] + 102
29 com.apple.AppKit 0x9572ea93 -[NSCell _sendActionFrom:] + 160
30 com.apple.AppKit 0x9572de50 -[NSCell trackMouse:inRect
fView:untilMouseUp:] + 2295
31 com.apple.AppKit 0x957b1351 -[NSButtonCell trackMouse:inRect
fView:untilMouseUp:] + 501
32 com.apple.AppKit 0x9572c893 -[NSControl mouseDown:] + 943
33 com.apple.AppKit 0x956f57b1 -[NSWindow sendEvent:] + 7533
34 com.apple.AppKit 0x9568d6ff -[NSApplication sendEvent:] + 4788
35 com.cockos.reaper 0x001e36c9 -[REAPERapp sendEvent:] + 297
36 com.apple.AppKit 0x9561ec82 -[NSApplication run] + 1007
37 com.apple.AppKit 0x958b318a NSApplicationMain + 1054
38 com.cockos.reaper 0x00002de9 _start + 208
39 com.cockos.reaper 0x00002d18 start + 40
Thread 1:: Dispatch queue: com.apple.libdispatch-manager
0 libsystem_kernel.dylib 0x94c2e90a kevent + 10
1 libdispatch.dylib 0x9c98dc58 _dispatch_mgr_invoke + 969
2 libdispatch.dylib 0x9c98c6a7 _dispatch_mgr_thread + 53