You shouldn't use absolute paths when working on Shiny apps you have to use relative paths instead (relative to your apps root folder), this is because when deployed on a server the app doesn't has access to your local files anymore.
After some reasearch through the internet, I found a lot of solutions that never worked for me.
Finally, I found a similar post to this where it was mentioned that especial characters weren´t recognize by shinyapp. And that´s true!!
In my dataset I had one variable with a name with "Ñ" and one of my declare inputs had a name with "ñ" (Both are related in the app). I changed the name of both variables for their translation in english.
And that´s all!!. Now my app deployed without problems and it´s working.
Thanks @andresrcs, with the setting options(encoding = "UTF-8") I didn't need to change the name of my variables.
I forgot to tell that I also realized two things:
I was installing my packages in a personal directory, so shiny wasn't able to find them.
I needed superuser permissions so I could install the packages with install.packages("pkgname", lib = .Library) without superuser permissions I was getting the message "path unwritable"
After this, shinyapp was able to find the packages. That's all.