We ran into this recently when attempting to deploy an OpsMgr 2012 SP1 agent to a SUSE Linux system. “One or more errors occurred. Failed to find a matching agent kit to install.”
When browsing to the DownloadedKits folder on the management server (c:\program files\System Center 2012\Operations Manager\Server\AgentManagement\UnixAgents\DownloadKits) we found that there were no SUSE files in the folder. When deploying agents to SUSE the folder should have at least the files shown below: 
Resolution: The correct versions of Unix/Linux management packs were not installed in the environment. We added the SUSE and SLES related management packs (version 7.4.3507.0) from the Operations Manager 2012 SP1 media and verified that the DownloadedKits folder was populated correctly then we re-distributed the agent successfully.