When it comes to electrical outlets, what does "Open Ground" mean? I got this reading with a tester i bought.?

The reason i ask is because of a few incidents that happened in my new apt that i just moved to. I connected my lcd tv to the wall, then i plugged my playstation 3 to the same outlet just the lower one. When i did this nothing happened everything was fine, then i called for my cable, when the cable man came to install the box up, i had disconnected my PS3 from the wall and the back of the tv, i had it with the HDMI plug, he used that plug to connect the box with, but keep in mind nothing was connected to the wall when he installed it. When he turned it on it turned on fine, both box and tv. after he left i disconnected the box, and connected my PS3 again using the same HDMI plug. the next day i bought myself another HDMI plug for the box, after getting back to my apt. i went to connect the box to the back of my tv on the 2nd HDMI input, my platstaion 3 was connected to the HDMI input 1, as i went to connect the box there was a loud POP! and bright sparks flew. my heart was at 100mph, i had no idea to what the hell just happened. When i turned on the tv it came on fine, but my PS3 was not, it was not displaying a picture. i took it back to the store, got me a 2nd one, this time i made sure nothing was connected to the wall, or so i thought, i had connected my new PS3 to the HDMI input in the back of the tv, input 1, it came on just fine, then i disconnected everything, i had unplugged my multi outlet surge Protector plug from the wall, my tv and PS3 was connected to it, so neither one had electricity running in them, but my box was connected directly to the wall, but was not turned on. This time i connected everything from the back of the tv first, i had component cables this time for my cable box and the HDMI for my PS3. As i went to connect my cables to the box, i had the cables on my hand then i grabbed the box and got a pretty strong shock that ran through my elbows, when i let go the box, it stopped, i had a bad feeling about it, so i disconnected the HDMI cable from the back of the PS3, and continued on to connect the Component cables, and before i could get one component plug fully in POP! and sparks. i was confused, nothing was connected to the outlet but the box, so i went and disconnected the HDMI plug from the tv and used the original PS3 plug which is a av cable (yellow,white,red) and when i went to connect it to the side of the tv, POP!!! again! and i noticed that the only thing connected was the component cables from the tv to the box. So at this point im guessing ok its the cable box that is the problem, so i completely disconnected it from the tv and outlet, and just connected the cable line straight to the tv, turned it on, and came on fine. Yes i had to again go to the store a day later and get a 3rd PS3. When i got home i did not dare to Connect it, so the next day i did, nothing was plugged into the outlet, i bought a new HDMI cable and connect it to the tv, and then to the PS3 nothing happened, i plug the TVS power cable to the power surge and the PS3, everything fine so far, then as i went to connect it to the wall, POP! and the circuit breakers turned off. so at this point i dont know wat is the problem. My PS3 is fine. i grabbed my Extension cord, heavy duty one, and connected the power surge to it, and plugged the Extension plug to a different outlet in the room. i currently have my PS3 and tv working fine, so today i bought this tester that lets u know if ur outlets r connected properly. and the code i got was the open ground code. could this be the problem?