It may not be the API at all -
Here's some commentary from someone in support on a case where someone saw this error while creating extracts with Desktop:
In previous experiences, when this error occurs, there are several potential causes. Typically, it occurs when a firewall or antivirus program is interfering with the Tableau Data Engine communication.
Are there any firewall or antivirus products that may be potentially interfering with the Tableau Data Engine communication? If so, please disable them when attempting to publish the view and let me know if the issue persists.
If disabling the firewall or antivirus does not resolve the issue then please provide the following additional information:
It would be really helpful if you put some breakpoints in your code so you could identify the method that is failing. Between the fact that you're using an unsupported wrapper and don't know where the error is coming from, there's going to be very little the folks here can do for you at this point.
Could you get Desktop installed on this machine and see if it fails there, too? Can you try the extract against a different data source? Maybe a local CSV file like we included in the samples?