Is the iOS SDK version 1.1.1 the latest version? There is no prebuilt library in the download from http://developer.authorize.net/integration/fifteenminutes/ios/.
There are warnings caused by bugs in the code:
TransactionDetailsType.m:159:58: warning: invalid conversion specifier "TransactionDetails.customer = @%\n"
TransactionDetailsType.m:160:56: warning: invalid conversion specifier "TransactionDetails.billTo = @%\n"
TransactionDetailsType.m:161:56: warning: invalid conversion specifier "TransactionDetails.shipTo = @%\n"
SendCustomerTransactionReceiptRequest.m:47:25: Data argument not used by format string
