Windows 2003 as a SPICE client

When I try to login to user portal and run console from Windows 2003 machine, I get an error in virt-viewer program:

controller connection failed. Error setting integrity: The specified datatype is invalid

Has anybody seen similar behavior? What could this mean? I took a look into the logs (engine.log and server.log in /var/log/ovirt-engine folder) - but they didn't show anything relevant while I was trying to connect to console. 

Thank you for any advice.