I have a business card from Maria Teresa with that address on it, and when I look the address up on Google Maps it looks correct, so I'm pretty sure that is the correct address. If you put "Rua Fonte Taurina, 89, Porto, Portugal" into
Google Maps it will show you the correct location.
I think that the walking instructions that I gave are correct, but I may have missed a detail or two. The last time I was in Porto I stayed at the Pestana Porto and walked daily to AVEPOD, but the directions are from memory and my memory isn't very good any more. :) There may be a very small side street that runs from Rua Fonte Taurina toward the water that I forgot in my directions. If memory serves, AVEPOD is probably 100 meters or so from the Pestana Porto.
From the street it looks very small and I guess it might look like a row house. The street itself is very narrow and dark, too, even on a bright day. But the door to the shop is clearly labeled so if you were at the right door I think you would have seen the sign.
Another way to get to it is to go to the tourist bureau on the corner of Rua da Alfandega and Rua do Infante dom Henrique. Walk down Rua da Alfandega toward the water and turn left onto Rua da Fonte Taurina. From this direction, AVEPOD will be approximately 10-15 meters down the street on the right (river) side.