parsing upload session finish error

Thanks for working with me on this, but my HTTPError comes back as...

HTTPError[nil]: nil: Optional(")

Here's my code....

//trying to upload a 33MB file in 5MB chunks

let data:NSData = NSFileManager.defaultManager().contentsAtPath(path)!
let chunkLength:UInt64 = 1024 * 1024 * 5 //in MB
let fileLength:UInt64 = UInt64(data.length)

print("FILE LENGTH: \(fileLength)")
print("CHUNK LENGTH: \(chunkLength)")

if (fileLength < chunkLength) {
print("LESS THAN CHUNK SIZE")
//Upload File
if let client = Dropbox.authorizedClient {
client.files.upload(path:destinationPath+uploadFilename!, body:data).response { response, error in
if let metadata = response {
completion()
} else {
print("UPLOAD ERROR(DropboxUploader.swift): \(error!)")
}
}
}

} else {

print("MORE THAN CHUNK SIZE")

var inputStream:NSInputStream = NSInputStream(data: data)
var position:UInt64 = 0
var loopCounter:UInt64 = 0

//Upload File
if let client = Dropbox.authorizedClient {

client.files.uploadSessionStart(body: inputStream).response { response, error in

print("UPLOAD SESSION STARTED") 

if let result = response {

print("UPLOAD SESSION START RESULT: \(result)")

while (position <= fileLength) {

print("POSITION \(position)")

client.files.uploadSessionAppend(sessionId: result.sessionId, offset: position, body: inputStream)

loopCounter++
print("LOOPCOUNTER: \(loopCounter)")
position = chunkLength * loopCounter

if (position >= UInt64(data.length)) {

position = UInt64(data.length)
print("POSITION \(position)")

client.files.uploadSessionAppend(sessionId: result.sessionId, offset: position, body: inputStream)

break
}

}

// we're ready to finish the upload and commit the file
client.files.uploadSessionFinish(cursor: Files.UploadSessionCursor(sessionId: result.sessionId, offset: position),
commit: Files.CommitInfo(path: destinationPath+uploadFilename!),
// no additional data to add at this point in this case
body:NSData()).response { response, error in

if let result = response {
print("Result: \(result)")
} else if let callError = error {
switch callError as CallError {
case .RouteError(let boxed, let requestId):
print("RouteError[\(requestId)]:")
switch boxed.unboxed as Files.UploadSessionFinishError {
case .Path(let fileLookupError):
print("Path: ")
switch fileLookupError {
case .MalformedPath(let malformedPathError):
print("MalformedPath: \(malformedPathError)")
case .Conflict(let writeConflictError):
print("Conflict:")
switch writeConflictError {
case .File:
print("File")
case .FileAncestor:
print("FileAncestor")
case .Folder:
print("Folder")
case .Other:
print("Other")
}
case .DisallowedName:
print("DisallowedName")
case .InsufficientSpace:
print("InsufficientSpace")
case .NoWritePermission:
print("NoWritePermission")
case .Other:
print("Other")
}
case .LookupFailed(let uploadSessionLookupError):
print("LookupFailed:")
switch uploadSessionLookupError {
case .Closed:
print("Closed")
case .IncorrectOffset(let uploadSessionOffsetError):
print("IncorrectOffset: \(uploadSessionOffsetError)")
case .NotFound:
print("NotFound")
case .Other:
print("Other")
}
case .Other:
print("Other")
}
case .BadInputError(let message, let requestId):
print("BadInputError[\(requestId)]: \(message)")
case .HTTPError(let code, let message, let requestId):
print("HTTPError[\(requestId)]: \(code): \(message)")
case .InternalServerError(let code, let message, let requestId):
print("InternalServerError[\(requestId)]: \(code): \(message)")
case .OSError(let err):
print("OSError: \(err)")
case .RateLimitError:
print("RateLimitError")
}
}

}
} else {
print("UPLOAD SESSION START ERROR(DropboxUploader.swift): \(error!)")
}
}
}
}

Here's the console output...

FILE LENGTH: 33700300

CHUNK LENGTH: 5242880

MORE THAN CHUNK SIZE

UPLOAD SESSION STARTED

UPLOAD SESSION START RESULT: {

    "session_id" = "AAAAAAAAAK-OwgQJFJJj8g";

}

POSITION 0

LOOPCOUNTER: 1

POSITION 5242880

LOOPCOUNTER: 2

POSITION 10485760

LOOPCOUNTER: 3

POSITION 15728640

LOOPCOUNTER: 4

POSITION 20971520

LOOPCOUNTER: 5

POSITION 26214400

LOOPCOUNTER: 6

POSITION 31457280

LOOPCOUNTER: 7

POSITION 33700300

HTTPError[nil]: nil: Optional(")