RevMail crashing in iOS stack - LC 6.6 - 7.0.1

[Richard Miller]

I am having a problem getting RevMail to work in an IOS LC stack. I have 
tried five different versions of LC (from 6.6 to 7.0.1), but each time I 
try the RevMail function, the system displays a blank email with only 
the subject line filled in. I can't get the email address or body to 
fill in. The blank email sits there for about 10 seconds, then I get a 
crash report (part of which is shown below).

Yosemite 10.10.2
Xcode  6.6.1

Not sure which version of the iOS SDK is installed (how would I identify 
that?), but I thought the latest version was installed when I installed 
Xcode.

The stack I am testing has only one card and one button, with this script:

on mouseUp
    revmail "wow at together.net",,"Help","data"
end mouseUp

Any ideas?

Thanks,
Richard Miller

------------------------------------------------------------------------------------
Process:               MailCompositionService [2034]
Path: 
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/Applications/MailCompositionService.app/MailCompositionService
Identifier:            MailCompositionService
Version:               1.0 (1.0)
Code Type:             X86-64 (Native)
Parent Process:        launchd_sim [1977]
Responsible:           launchd_sim [1977]
User ID:               503

Date/Time:             2015-02-12 09:59:36.980 -0500
OS Version:            Mac OS X 10.10.2 (14C109)
Report Version:        11
Anonymous UUID:        DE114208-C273-8696-1D5B-1CF792FDBE37


Time Awake Since Boot: 61000 seconds

Crashed Thread:        0  Dispatch queue: com.apple.main-thread

Exception Type:        EXC_CRASH (SIGABRT)
Exception Codes:       0x0000000000000000, 0x0000000000000000

Application Specific Information:
*** Terminating app due to uncaught exception 
'NSInvalidArgumentException', reason: '*** -[NSRegularExpression 
enumerateMatchesInString:options:range:usingBlock:]: nil argument'
terminating with uncaught exception of type NSException
abort() called
CoreSimulator 110.4 - Device: iPhone 5s - Runtime: iOS 8.1 (12B411) - 
DeviceType: iPhone 5s