HDMI Length an issue or HDMI cable type?

Basically here is my problem. I mounted a 42 inch LCD in my living room, I went out and bought a 15 foot HDMI cable to run through the wall.  The cable manufacturer states it’s an in wall cable shielded with woven thread around cable and all.

I connected to WD Live and no input detected by my TV. I have a similar cable 10 footer, I was using with WDbox and TV before worked perfectly just not long enough. I thought maybe this new 15 foot cable was bad. I pulled it out of wall connected it to my computer and LCD computer monitor via HDMI and the 15 footer worked fine?

Anyone have a suggestion for this one???

one more thing, when I plug in the power on the WD Live Plus, it shows the splash screen. Then when it switches to the menu screen goes blank.

I use a 15 meter (45+ feet) hdmi cable without any issues. It sounds like a wdtv problem not a cable problem. ? All I can suggest is update to latest firmware, do both reboots, select hdmi in menu and cross fingers ?