To perform backups to a DR Series system, the clients should be running Solaris 10 Update 10 or later.
Client OS is running Solaris 10 releases before Update 10 and is probably unpatched.
Only Solaris 10 Update 10 and above, and Solaris 11 is officially supported for RDA backups.
How to check if OS is running on which release:
1. cat /etc/release
Upgrade the Solaris 10 OS to the latest release.
The compatibility of RDA plug-in for Solaris (x86 and SPARC) is listed in the link below.
If upgrading is not an option, patch the Solaris 10 OS using the latest recommended patch bundle provided by Oracle. Note that this will not upgrade OS release. There have been cases where RDA will start working after patching. If this does not work, please upgrade the Solaris 10 OS to the latest release.