On the Primary server, the InteropJava.log is filled with "Unable to find cluster US194WB111".
What do you mean by primary server ? and looks like your cluster information with shared services is lost or your CASSecurity.exe got terminated which deals with authentication mechanism between your Shared Services and Application Server/Application. (If you mean primary server is first one in your cluster then are you able to launch the application smartview by using second server ?)
When you face this error , do you see those services are still running ?
since when you starting facing this issue ? were there any patches being applied or changes made ?
Could you please post your server configuration details ? Are these components installed on all the servers (Cluster)?
1. Foundation Services(Workspace, Shared Service)
2. Financial Reporting
4. EPMA Web
5. HFM Web
6. Calc Manager Web