I got error  while I was playing my 1st Blu-ray disk on my HP Pavilion DV5 and connecting it to my Samsung LCD LA32b650T “This content is protected. The content is not allowed to play in current display mode.” and after investigation I found that This error is simple because HDMI display uses authentication protocol HDCP which detected additional HDMI device is connected to the display like (xbox, DVD player) so simple remove connected devices and re-run your Blu-ray disk.

source is below:

When playing high-definition videos, such as Blu-ray or HD DVD movies, an error message about protected content displays. The following list shows some of the messages that can appear:

• This content is protected. The content is not allowed to play in current display mode.

• Stop. Your display environment does not support protected content playback.

• This program includes content protection that restricts viewing…

• HDMI HDCP Key – Authentication failed.

These types of messages occur because of HDCP. High-bandwidth Digital Content Protection (HDCP) – a method that is used to protect high-definition content from being copied as it passes from the computer to the monitor or HD TV. Commercial Blu-ray and HD DVD movies are protected by HDCP when played.

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01530801&cc=us&lc=en&dlc=en&product=3867599