So I managed to download the work, and it works. I stopped using simple authentication and decided to use an authentication token, which you can generate in the user profile settings. This did the trick Working Command for cURL:
curl -v --header "X-Rundeck-Auth-Token:<token-value>" -F xmlBatch=@ "X:\job.xml" http://xxx.xxx.xxx.xxx/api/1/jobs/import
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