OO fails to connect to vCenter API

Trying to connect to a vCenter 5.5 server with OO. OO fails with this message:

Couldn't connect to VIM service: VI SDK invoke exception:org.dom4j.DocumentException: Error on line 1 of document  : White spaces are required between publicId and systemId. Nested exception: White spaces are required between publicId and systemId.

If I try to connect with PowerCLI, or RVTools, or any other REST API client - it works no problem.

I am using OO Virtualization CP 1.8, and none of the flows work. I tried to use a Deprecated Flow - and it will get through the logon stage - but fails to execute any commands with the same message above.

Has anyone seen an issue like this before?