I assume we are talking about Windows player here?
Could you please tell us what version of CMS and Windows client are you using?
Is your player shown as logged in? (check mark in logged in column)
The 'unknown display status' means that 1 I don't think you have 1.7.4 CMS version and 2 that the player is not up to date with schedule/content from CMS (it should be trying to download it).
Few things can cause this, please answer my questions then we will try to solve this issue.