This will be a problem caused by the JSON-RPC connection (which itself runs over HTTP) failing before the file has finished being transferred. You can check the Node system for a timeout that could be causing this.
Alternatively, use MultiChain 2.0 (alphas) which allows large pieces of data to be delivered to MultiChain via the file system, using the binary cache. Search the page below for createbinarycache, appendbinarycache, deletebinarycache and "cache" (with the quotes) to learn more:
https://www.multichain.com/developers/multichain-2-0-preview-releases/