Epson R1900 Not Recognizing Ink

I just got and Epson R1900 and the first batch of ink worked without any hitches (yeah, and the prints are gorgeous). However, I ordered some Epson ink from a major photo supply place's website, and my printer wouldn't recognize the cyan cartridge. I bought a cyan cartridge from a local store and it is working just fine. Then my yellow ran out, so I replaced it with ink from the internet order, and again, my printer wouldn't recognize the cartridge. I had another yellow cartridge from the same internet order, and it worked fine for several prints, then suddenly it says that it's out of yellow. The internet order box was beaten up, but the cartridges looked just fine. It seems odd to me that different ink cartridges would be defective. I am sure that I'm installing the ink correctly, by the way. Anyone else having similar problems? Any suggestions?