crash in setEventArgs

more info, seems to be crashing in the string handling case:

Application Specific Information:
objc[58283]: garbage collection is OFF
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSArrayM insertObject:atIndex:]: object cannot be nil'
*** First throw call stack:
(
 0 CoreFoundation 0x00007fff9602af56 __exceptionPreprocess + 198
 1 libobjc.A.dylib 0x00007fff89ef3dee objc_exception_throw + 43
 2 CoreFoundation 0x00007fff95fd1ab8 -[__NSArrayM insertObject:atIndex:] + 296
 3 com.ubuntu.one.fsevents 0x0000000100002505 -[FSEvent setEventArgs:withOffset:withTotalSize:] + 741
 4 com.ubuntu.one.fsevents 0x0000000100004583 -[FSEventDispatcher run] + 851
 5 Foundation 0x00007fff95c7872a -[NSThread main] + 68
 6 Foundation 0x00007fff95c786a2 __NSThread__main__ + 1575
 7 libsystem_c.dylib 0x00007fff906bc8bf _pthread_start + 335
 8 libsystem_c.dylib 0x00007fff906bfb75 thread_start + 13
)

Thread 3 Crashed:
0 libsystem_kernel.dylib 0x00007fff911b2ce2 __pthread_kill + 10
1 libsystem_c.dylib 0x00007fff906be7d2 pthread_kill + 95
2 libsystem_c.dylib 0x00007fff906afa7a abort + 143
3 libc++abi.dylib 0x00007fff8d2767bc abort_message + 214
4 libc++abi.dylib 0x00007fff8d273fcf default_terminate() + 28
5 libobjc.A.dylib 0x00007fff89ef4249 _objc_terminate + 94
6 libc++abi.dylib 0x00007fff8d274001 safe_handler_caller(void (*)()) + 11
7 libc++abi.dylib 0x00007fff8d27405c std::terminate() + 16
8 libc++abi.dylib 0x00007fff8d275152 __cxa_throw + 114
9 libobjc.A.dylib 0x00007fff89ef3f0a objc_exception_throw + 327
10 com.apple.CoreFoundation 0x00007fff95fd1ab8 -[__NSArrayM insertObject:atIndex:] + 296
11 com.ubuntu.one.fsevents 0x0000000100002505 -[FSEvent setEventArgs:withOffset:withTotalSize:] + 741 (FSEvent.m:225)
12 com.ubuntu.one.fsevents 0x0000000100004583 -[FSEventDispatcher run] + 851 (FSEventDispatcher.m:333)
13 com.apple.Foundation 0x00007fff95c7872a -[NSThread main] + 68
14 com.apple.Foundation 0x00007fff95c786a2 __NSThread__main__ + 1575
15 libsystem_c.dylib 0x00007fff906bc8bf _pthread_start + 335
16 libsystem_c.dylib 0x00007fff906bfb75 thread_start + 13