My guess is the "X" is referring to some of the PSR series radios or the RS Pro-107. They all use the "X" in the software library to display items that cannot be monitored by that particular scanner. In the case of the PSR 800, that would be encrypted talkgroups or digital/analog formats that cannot be received by scanners such as Provoice, etc.
In this case, since none of the above with the PSR 800 appears to apply with those systems, I'd say the OP has an analog scanner such as the PSR 700 or Pro-107 and is trying to import digital talkgroups and thus the "X" is being displayed next to them because those aren't digital scanners and cannot receive the digital talkgroups.