Let me guess, Aquarium pharmecutical test kit? Petsmart/petco? Maybe even from walmart?
Some test kit's, such as the one mentioned above, are going to be somewhat innaccurate the majority of the time, and all the time, they are difficult to read. My ammonia test (AP) shows .25 in my tank all the time. I know it's not there, but "the test says so". You can get a second opinion with another test kit. Ammonia would not cause the green pea soup, but the dead fish you mentioned in the other thread may, as well as an ammonia spike, so I would recommend the second opinion.