From the release notes:
Known Issues
SSO login functionality throws 500 Internal Server Error if the SDK code is executed from a Linux environment. If you call the VcloudClient -> ssoLogin method, the SDK throws a 500 Internal Server Error if executed from a Linux environment. To avoid this behavior, upgrade the commons-code-1.4.jar to commons-codec-1.5.jar/commons-codec-1.6.jar.
I updated commons-codec and no more 500 error.