Can one antivirus mark another as infectious object?

Sometimes they will mark another antivirus as a threat. I have 2 antivirus installed, but only ever have one actually loaded and running, so they never interfere. I also use Spybot and AdAware for spyware, and every once in a while AdAware will claim that Spybot is a threat. So yes, it is possible, and if you know for sure that your Panda file is safe then I wouldn't worry about it. I think that Panda may be showing up as a Trojan simply because when it is installed it will make certain changes to your system and AVG is simply detecting that, and calling it a Trojan. That doesn't mean that Panda is infected.