lestroso, great that you have it working but I am not sure you are working in the best possible manner.
The './' in front of an executable's name indicates you want to use the executable in the current working directory. As you have not set a path to the two wav files, its implied they are also in the current working directory.
As a general rule, in *nix we try to keep data and executable files in different places. In your case, the lazres executable should be where you first installed it (or built it if you build lazarus from source). It sits safely there out of the way until needed. *nix does not normally look for an executable in your working directory because thats where you have your data file, perhaps files that change a lot, maybe ones you are editing.
So, from what you say above, it looks to me like you have copied lazres (the executable) from where you first started into that director called lasres ? And put your wav files in there too ?
Far better, IMHO, to have just your working data files in there, the two wav files plus whatever else you are working on. And, when you call set a path to where ever lasres is.
I built Lazarus from source on Mac and I don't have my Mac with me but from memory (dodgy), I'd something like -
~/bin/Lazarus/lazarus_2_0_4/tools/lazres resorce.res sound1.wav sound2.wav
Davo