I don't know if the install script for this is a MythTV script or a KnoppMyth script but when you install KnoppMyth after the first reboot it walks you through a terminal based setup script that creates all the nessary configuration and setup of MythTV.

At one point it asked me for my cable TV provider information, I chose the wrong settings and maybe that is why I cannot get the TV card to work. What script can I run to resetup the TV card options? The MythTV GUI does not have the option to change these settings.

The major problem that may or may not be caused by this is that when I try to watch TV it tells me that all available cards are in use, but they are not.

I would like to re-run the TV card setup script and see if that fixes my TV problem. I know I selected the wrong cable TV provider option but if that is not the cause of the TV error please let me know.

From the frontend:
Alt+2 to stop the backend
Alt+S to enter backend setup
when done, Alt+3 to re-start the backend.

I think he means the text-based stuff that comes up after the card configuration, like when it prompts for the type of remote.

I don't believe the text based stuff will cause that error, but I don't remember the name of the script for the cable provider.

It's probably one of the *.sh files in the /usr/local/bin directory, but I can't figure out which one.

If you use a grabber such as DataDirect then this isn't a problem. Perform the steps thornsoft outlined and enter the appropriate information in Video Sources.

This sounds more like the tuner cards or input connections not being configured correctly, not the video source. What tuner card(s) are you using?

I don't know what card it is. I bought it used and it has no name on it but it uses the BTTV drivers and worked great with my older KnoppMyth install.

lspci only says this about it
00:07.0 Multimedia video controller: Brooktree Corporation Bt878 Video Capture (rev 02)
00:07.1 Multimedia controller: Brooktree Corporation Bt878 Audio Capture (rev 02)

Sounds like a missing input connection.... See the walk through here: http://www.knoppmythwiki.org/index.php?page=BlackScreenWatchingTV